From patchwork Tue Jun 2 11:33:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 213830 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E362EC433E0 for ; Tue, 2 Jun 2020 11:34:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C88FA2068D for ; Tue, 2 Jun 2020 11:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726311AbgFBLeT (ORCPT ); Tue, 2 Jun 2020 07:34:19 -0400 Received: from mx2.suse.de ([195.135.220.15]:37870 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgFBLeT (ORCPT ); Tue, 2 Jun 2020 07:34:19 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 5B947AD5D; Tue, 2 Jun 2020 11:34:20 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , Doug Gilbert , Daniel Wagner , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 2/6] target_core_pscsi: use __scsi_device_lookup() Date: Tue, 2 Jun 2020 13:33:07 +0200 Message-Id: <20200602113311.121513-3-hare@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200602113311.121513-1-hare@suse.de> References: <20200602113311.121513-1-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Instead of walking the list of devices manually use the helper function to return the device directly. Signed-off-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reviewed-by: Bart van Assche --- drivers/target/target_core_pscsi.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 4e37fa9b409d..38799e47b590 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -496,11 +496,9 @@ static int pscsi_configure_device(struct se_device *dev) } spin_lock_irq(sh->host_lock); - list_for_each_entry(sd, &sh->__devices, siblings) { - if ((pdv->pdv_channel_id != sd->channel) || - (pdv->pdv_target_id != sd->id) || - (pdv->pdv_lun_id != sd->lun)) - continue; + sd = __scsi_device_lookup(sh, pdv->pdv_channel_id, + pdv->pdv_target_id, pdv->pdv_lun_id); + if (sd) { /* * Functions will release the held struct scsi_host->host_lock * before calling calling pscsi_add_device_to_list() to register From patchwork Tue Jun 2 11:33:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 213828 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B816C433E1 for ; Tue, 2 Jun 2020 11:34:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B76C2068D for ; Tue, 2 Jun 2020 11:34:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726580AbgFBLeW (ORCPT ); Tue, 2 Jun 2020 07:34:22 -0400 Received: from mx2.suse.de ([195.135.220.15]:37880 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726139AbgFBLeV (ORCPT ); Tue, 2 Jun 2020 07:34:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 5BFBCAD72; Tue, 2 Jun 2020 11:34:20 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , Doug Gilbert , Daniel Wagner , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 3/6] scsi: move target device list to xarray Date: Tue, 2 Jun 2020 13:33:08 +0200 Message-Id: <20200602113311.121513-4-hare@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200602113311.121513-1-hare@suse.de> References: <20200602113311.121513-1-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Use xarray for device lookup by target. If the LUN only uses the first two levels (ie 32 bit) it can be used directly as the index into the xarray. LUNs using more than two levels will overflow the xarray index; they will be stored in the next free index in the xarray. Signed-off-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn --- drivers/scsi/scsi.c | 35 +++++++++++++++++++++-------------- drivers/scsi/scsi_lib.c | 9 ++++----- drivers/scsi/scsi_scan.c | 5 +++-- drivers/scsi/scsi_sysfs.c | 36 +++++++++++++++++++++++++++++++++--- include/scsi/scsi_device.h | 4 ++-- 5 files changed, 63 insertions(+), 26 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index d601424e32b2..a3e01708744f 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -601,13 +601,14 @@ static struct scsi_target *__scsi_target_lookup(struct Scsi_Host *shost, void starget_for_each_device(struct scsi_target *starget, void *data, void (*fn)(struct scsi_device *, void *)) { - struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); struct scsi_device *sdev; + unsigned long lun_idx = 0; - shost_for_each_device(sdev, shost) { - if ((sdev->channel == starget->channel) && - (sdev->id == starget->id)) - fn(sdev, data); + xa_for_each(&starget->__devices, lun_idx, sdev) { + if (scsi_device_get(sdev)) + continue; + fn(sdev, data); + scsi_device_put(sdev); } } EXPORT_SYMBOL(starget_for_each_device); @@ -629,14 +630,11 @@ EXPORT_SYMBOL(starget_for_each_device); void __starget_for_each_device(struct scsi_target *starget, void *data, void (*fn)(struct scsi_device *, void *)) { - struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); struct scsi_device *sdev; + unsigned long lun_idx = 0; - __shost_for_each_device(sdev, shost) { - if ((sdev->channel == starget->channel) && - (sdev->id == starget->id)) - fn(sdev, data); - } + xa_for_each(&starget->__devices, lun_idx, sdev) + fn(sdev, data); } EXPORT_SYMBOL(__starget_for_each_device); @@ -658,12 +656,21 @@ EXPORT_SYMBOL(__starget_for_each_device); struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, u64 lun) { - struct scsi_device *sdev; + struct scsi_device *sdev = NULL; + unsigned long lun_idx = 0; + + if (lun < UINT_MAX) + sdev = xa_load(&starget->__devices, lun); + if (sdev && sdev->lun == lun) { + if (sdev->sdev_state == SDEV_DEL) + sdev = NULL; + return sdev; + } - list_for_each_entry(sdev, &starget->devices, same_target_siblings) { + xa_for_each(&starget->__devices, lun_idx, sdev) { if (sdev->sdev_state == SDEV_DEL) continue; - if (sdev->lun ==lun) + if (sdev->lun == lun) return sdev; } diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index c163fa22267c..9337422d864a 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -361,9 +361,9 @@ static void scsi_kick_queue(struct request_queue *q) static void scsi_single_lun_run(struct scsi_device *current_sdev) { struct Scsi_Host *shost = current_sdev->host; - struct scsi_device *sdev, *tmp; + struct scsi_device *sdev; struct scsi_target *starget = scsi_target(current_sdev); - unsigned long flags; + unsigned long flags, lun_idx = 0; spin_lock_irqsave(shost->host_lock, flags); starget->starget_sdev_user = NULL; @@ -380,8 +380,7 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev) spin_lock_irqsave(shost->host_lock, flags); if (starget->starget_sdev_user) goto out; - list_for_each_entry_safe(sdev, tmp, &starget->devices, - same_target_siblings) { + xa_for_each(&starget->__devices, lun_idx, sdev) { if (sdev == current_sdev) continue; if (scsi_device_get(sdev)) @@ -390,7 +389,7 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev) spin_unlock_irqrestore(shost->host_lock, flags); scsi_kick_queue(sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); - + scsi_device_put(sdev); } out: diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 9fc35b6cbc30..51faeb0dd742 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -235,7 +235,6 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, mutex_init(&sdev->state_mutex); sdev->sdev_state = SDEV_CREATED; INIT_LIST_HEAD(&sdev->siblings); - INIT_LIST_HEAD(&sdev->same_target_siblings); INIT_LIST_HEAD(&sdev->starved_entry); INIT_LIST_HEAD(&sdev->event_list); spin_lock_init(&sdev->list_lock); @@ -327,6 +326,8 @@ static void scsi_target_dev_release(struct device *dev) struct device *parent = dev->parent; struct scsi_target *starget = to_scsi_target(dev); + WARN_ON(!xa_empty(&starget->__devices)); + xa_destroy(&starget->__devices); kfree(starget); put_device(parent); } @@ -414,7 +415,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, starget->id = id; starget->channel = channel; starget->can_queue = 0; - INIT_LIST_HEAD(&starget->devices); + xa_init_flags(&starget->__devices, XA_FLAGS_ALLOC); starget->state = STARGET_CREATED; starget->scsi_level = SCSI_2; starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED; diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 83bdcb032853..5b009ec97250 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -433,7 +433,8 @@ static void scsi_device_cls_release(struct device *class_dev) static void scsi_device_dev_release_usercontext(struct work_struct *work) { - struct scsi_device *sdev; + struct scsi_device *sdev, *tmp_sdev; + struct scsi_target *starget; struct device *parent; struct list_head *this, *tmp; struct scsi_vpd *vpd_pg80 = NULL, *vpd_pg83 = NULL; @@ -441,6 +442,7 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) unsigned long flags; sdev = container_of(work, struct scsi_device, ew.work); + starget = sdev->sdev_target; scsi_dh_release_device(sdev); @@ -448,7 +450,12 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) spin_lock_irqsave(sdev->host->host_lock, flags); list_del(&sdev->siblings); - list_del(&sdev->same_target_siblings); + /* Use cmpxchg to avoid accidental deletion */ + tmp_sdev = xa_cmpxchg(&starget->__devices, sdev->lun_idx, sdev, + NULL, GFP_ATOMIC); + if (tmp_sdev != sdev) + sdev_printk(KERN_WARNING, sdev, + "index %u reassigned!\n", sdev->lun_idx); list_del(&sdev->starved_entry); spin_unlock_irqrestore(sdev->host->host_lock, flags); @@ -1593,6 +1600,7 @@ void scsi_sysfs_device_initialize(struct scsi_device *sdev) unsigned long flags; struct Scsi_Host *shost = sdev->host; struct scsi_target *starget = sdev->sdev_target; + int ret = -ERANGE; device_initialize(&sdev->sdev_gendev); sdev->sdev_gendev.bus = &scsi_bus_type; @@ -1620,7 +1628,29 @@ void scsi_sysfs_device_initialize(struct scsi_device *sdev) transport_setup_device(&sdev->sdev_gendev); spin_lock_irqsave(shost->host_lock, flags); - list_add_tail(&sdev->same_target_siblings, &starget->devices); + if (sdev->lun < UINT_MAX) { + sdev->lun_idx = sdev->lun; + ret = xa_insert(&starget->__devices, (unsigned int)sdev->lun, + sdev, GFP_ATOMIC); + } + /* + * Use a free index if the LUN is larger than 32 bit or + * if the index is already taken. Leave the lower 256 + * entries free to avoid collisions. + */ + if (ret) { + struct xa_limit scsi_lun_limit = { + .min = 256, + .max = UINT_MAX, + }; + ret = xa_alloc(&starget->__devices, &sdev->lun_idx, + sdev, scsi_lun_limit, GFP_ATOMIC); + } + if (ret) { + shost_printk(KERN_ERR, shost, + "LUN index %u:%u:%llu allocation error %d\n", + sdev_channel(sdev), sdev_id(sdev), sdev->lun, ret); + } list_add_tail(&sdev->siblings, &shost->__devices); spin_unlock_irqrestore(shost->host_lock, flags); /* diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 8cb31bbd8a82..56801661f481 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -104,7 +104,6 @@ struct scsi_device { /* the next two are protected by the host->host_lock */ struct list_head siblings; /* list of all devices on this host */ - struct list_head same_target_siblings; /* just the devices sharing same target id */ atomic_t device_busy; /* commands actually active on LLDD */ atomic_t device_blocked; /* Device returned QUEUE_FULL. */ @@ -123,6 +122,7 @@ struct scsi_device { u16 id, channel; u64 lun; + unsigned int lun_idx; /* Index into target device xarray */ unsigned int manufacturer; /* Manufacturer of device, for using * vendor-specific cmd's */ unsigned sector_size; /* size in bytes */ @@ -285,7 +285,7 @@ enum scsi_target_state { struct scsi_target { struct scsi_device *starget_sdev_user; struct list_head siblings; - struct list_head devices; + struct xarray __devices; struct device dev; struct kref reap_ref; /* last put renders target invisible */ u16 channel; From patchwork Tue Jun 2 11:33:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 213827 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5775C433DF for ; Tue, 2 Jun 2020 11:34:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1C2A2068D for ; Tue, 2 Jun 2020 11:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726625AbgFBLeY (ORCPT ); Tue, 2 Jun 2020 07:34:24 -0400 Received: from mx2.suse.de ([195.135.220.15]:37938 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgFBLeV (ORCPT ); Tue, 2 Jun 2020 07:34:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B1D8DAE18; Tue, 2 Jun 2020 11:34:20 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , Doug Gilbert , Daniel Wagner , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 5/6] scsi_error: use xarray lookup instead of wrappers Date: Tue, 2 Jun 2020 13:33:10 +0200 Message-Id: <20200602113311.121513-6-hare@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200602113311.121513-1-hare@suse.de> References: <20200602113311.121513-1-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org For SCSI EH most shost_for_each_sdev() calls are just to filter out devices for specific targets or channels. These calls can be made more efficient using direct xarray lookup and iterators. Signed-off-by: Hannes Reinecke --- drivers/scsi/scsi.c | 2 +- drivers/scsi/scsi_error.c | 35 ++++++++++++++++++++++------------- drivers/scsi/scsi_priv.h | 2 ++ 3 files changed, 25 insertions(+), 14 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 6a1d8c6bd8f9..296cecd61d3a 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -652,7 +652,7 @@ EXPORT_SYMBOL(__scsi_iterate_devices_unlocked); * @id: ID of the target * */ -static struct scsi_target *__scsi_target_lookup(struct Scsi_Host *shost, +struct scsi_target *__scsi_target_lookup(struct Scsi_Host *shost, u16 channel, u16 id) { return xa_load(&shost->__targets, (channel << 16) | id); diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 927b1e641842..02605c848365 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -643,7 +643,9 @@ EXPORT_SYMBOL_GPL(scsi_check_sense); static void scsi_handle_queue_ramp_up(struct scsi_device *sdev) { struct scsi_host_template *sht = sdev->host->hostt; + struct scsi_target *starget; struct scsi_device *tmp_sdev; + unsigned long lun_idx = 0; if (!sht->track_queue_depth || sdev->queue_depth >= sdev->max_queue_depth) @@ -661,10 +663,9 @@ static void scsi_handle_queue_ramp_up(struct scsi_device *sdev) * Walk all devices of a target and do * ramp up on them. */ - shost_for_each_device(tmp_sdev, sdev->host) { - if (tmp_sdev->channel != sdev->channel || - tmp_sdev->id != sdev->id || - tmp_sdev->queue_depth == sdev->max_queue_depth) + starget = __scsi_target_lookup(sdev->host, sdev->channel, sdev->id); + xa_for_each(&starget->__devices, lun_idx, tmp_sdev) { + if (tmp_sdev->queue_depth == sdev->max_queue_depth) continue; scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1); @@ -675,14 +676,15 @@ static void scsi_handle_queue_ramp_up(struct scsi_device *sdev) static void scsi_handle_queue_full(struct scsi_device *sdev) { struct scsi_host_template *sht = sdev->host->hostt; + struct scsi_target *starget = sdev->sdev_target; struct scsi_device *tmp_sdev; + unsigned long lun_idx = 0; if (!sht->track_queue_depth) return; - shost_for_each_device(tmp_sdev, sdev->host) { - if (tmp_sdev->channel != sdev->channel || - tmp_sdev->id != sdev->id) + xa_for_each(&starget->__devices, lun_idx, tmp_sdev) { + if (tmp_sdev->sdev_state == SDEV_DEL) continue; /* * We do not know the number of commands that were at @@ -2273,10 +2275,16 @@ int scsi_error_handler(void *data) */ void scsi_report_bus_reset(struct Scsi_Host *shost, int channel) { + struct scsi_target *starget; struct scsi_device *sdev; + unsigned long tid = 0; - __shost_for_each_device(sdev, shost) { - if (channel == sdev_channel(sdev)) + xa_for_each(&shost->__targets, tid, starget) { + unsigned long lun_idx = 0; + + if (starget->channel != channel) + continue; + xa_for_each(&starget->__devices, lun_idx, sdev) __scsi_report_device_reset(sdev, NULL); } } @@ -2306,13 +2314,14 @@ EXPORT_SYMBOL(scsi_report_bus_reset); */ void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target) { + struct scsi_target *starget; struct scsi_device *sdev; + unsigned long lun_idx = 0; - __shost_for_each_device(sdev, shost) { - if (channel == sdev_channel(sdev) && - target == sdev_id(sdev)) + starget = __scsi_target_lookup(shost, channel, target); + if (starget) + xa_for_each(&starget->__devices, lun_idx, sdev) __scsi_report_device_reset(sdev, NULL); - } } EXPORT_SYMBOL(scsi_report_device_reset); diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 22b6585e28b4..0a87c95359aa 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -49,6 +49,8 @@ enum scsi_devinfo_key { SCSI_DEVINFO_SPI, }; +extern struct scsi_target *__scsi_target_lookup(struct Scsi_Host *shost, + u16 channel, u16 id); extern blist_flags_t scsi_get_device_flags(struct scsi_device *sdev, const unsigned char *vendor, const unsigned char *model); From patchwork Tue Jun 2 11:33:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 213829 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AFC2C433E0 for ; Tue, 2 Jun 2020 11:34:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41F462068D for ; Tue, 2 Jun 2020 11:34:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726429AbgFBLeV (ORCPT ); Tue, 2 Jun 2020 07:34:21 -0400 Received: from mx2.suse.de ([195.135.220.15]:37940 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726320AbgFBLeV (ORCPT ); Tue, 2 Jun 2020 07:34:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B1D3EAE17; Tue, 2 Jun 2020 11:34:20 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , Doug Gilbert , Daniel Wagner , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 6/6] scsi: avoid pointless memory allocation in scsi_alloc_target() Date: Tue, 2 Jun 2020 13:33:11 +0200 Message-Id: <20200602113311.121513-7-hare@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200602113311.121513-1-hare@suse.de> References: <20200602113311.121513-1-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org As we already know the index of the requested target in scsi_alloc_target() we can try to fetch it first before trying to allocate a new one. This will save us a pointless memory allocation in case the target is already present and uncontended. Signed-off-by: Hannes Reinecke --- drivers/scsi/scsi_scan.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 8afb71c036d5..41818111808e 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -387,7 +387,7 @@ static void scsi_target_reap_ref_put(struct scsi_target *starget) * is responsible for both reaping and doing a last put */ static struct scsi_target *scsi_alloc_target(struct device *parent, - int channel, uint id) + u16 channel, u16 id) { struct Scsi_Host *shost = dev_to_shost(parent); struct device *dev = NULL; @@ -397,7 +397,23 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, struct scsi_target *starget; struct scsi_target *found_target; int error, ref_got; - unsigned long tid; + unsigned long tid = (channel << 16) | id; + + /* + * Try if the target is already present, and save us + * a pointless memory allocation if so. + */ + spin_lock_irqsave(shost->host_lock, flags); + found_target = xa_load(&shost->__targets, tid); + if (found_target) { + get_device(&found_target->dev); + if (kref_get_unless_zero(&found_target->reap_ref)) { + spin_unlock_irqrestore(shost->host_lock, flags); + return found_target; + } + put_device(&found_target->dev); + } + spin_unlock_irqrestore(shost->host_lock, flags); starget = kzalloc(size, GFP_KERNEL); if (!starget) { @@ -418,7 +434,6 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, starget->state = STARGET_CREATED; starget->scsi_level = SCSI_2; starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED; - tid = scsi_target_index(starget); retry: spin_lock_irqsave(shost->host_lock, flags); found_target = xa_load(&shost->__targets, tid);