| Message ID | 20220624155226.2889613-2-arnd@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | phase out CONFIG_VIRT_TO_BUS | expand |
On 6/24/22 09:52, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > The BusLogic driver is the last remaining driver that relies on the > deprecated bus_to_virt() function, which in turn only works on a few > architectures, and is incompatible with both swiotlb and iommu support. > > Before commit 391e2f25601e ("[SCSI] BusLogic: Port driver to 64-bit."), > the driver had a dependency on x86-32, presumably because of this > problem. However, the change introduced another bug that made it still > impossible to use the driver on any 64-bit machine. > > This was in turn fixed in commit 56f396146af2 ("scsi: BusLogic: Fix > 64-bit system enumeration error for Buslogic"), 8 years later, which > shows that there are not a lot of users. > > Maciej is still using the driver on 32-bit hardware, and Khalid mentioned > that the driver works with the device emulation used in VirtualBox > and VMware. Both of those only emulate it for Windows 2000 and older > operating systems that did not ship with the better LSI logic driver. > > Do a minimum fix that searches through the list of descriptors to find > one that matches the bus address. This is clearly as inefficient as > was indicated in the code comment about the lack of a bus_to_virt() > replacement. A better fix would likely involve changing out the entire > descriptor allocation for a simpler one, but that would be much > more invasive. > > Cc: Maciej W. Rozycki <macro@orcam.me.uk> > Cc: Matt Wang <wwentao@vmware.com> > Tested-by: Khalid Aziz <khalid@gonehiking.org> > Reviewed-by: Robin Murphy <robin.murphy@arm.com> > Reviewed-by: Hannes Reinecke <hare@suse.de> > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > v3: Address issues pointed out by Khalid Aziz > v2: Attempt to fix the driver instead of removing it > --- > drivers/scsi/BusLogic.c | 35 +++++++++++++++++++++++------------ > drivers/scsi/Kconfig | 2 +- > 2 files changed, 24 insertions(+), 13 deletions(-) > This looks good. Acked-by: Khalid Aziz <khalid@gonehiking.org> > diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c > index a897c8f914cf..f2abffce2659 100644 > --- a/drivers/scsi/BusLogic.c > +++ b/drivers/scsi/BusLogic.c > @@ -2515,12 +2515,26 @@ static int blogic_resultcode(struct blogic_adapter *adapter, > return (hoststatus << 16) | tgt_status; > } > > +/* > + * turn the dma address from an inbox into a ccb pointer > + * This is rather inefficient. > + */ > +static struct blogic_ccb * > +blogic_inbox_to_ccb(struct blogic_adapter *adapter, struct blogic_inbox *inbox) > +{ > + struct blogic_ccb *ccb; > + > + for (ccb = adapter->all_ccbs; ccb; ccb = ccb->next_all) > + if (inbox->ccb == ccb->dma_handle) > + break; > + > + return ccb; > +} > > /* > blogic_scan_inbox scans the Incoming Mailboxes saving any > Incoming Mailbox entries for completion processing. > */ > - > static void blogic_scan_inbox(struct blogic_adapter *adapter) > { > /* > @@ -2540,17 +2554,14 @@ static void blogic_scan_inbox(struct blogic_adapter *adapter) > enum blogic_cmplt_code comp_code; > > while ((comp_code = next_inbox->comp_code) != BLOGIC_INBOX_FREE) { > - /* > - We are only allowed to do this because we limit our > - architectures we run on to machines where bus_to_virt( > - actually works. There *needs* to be a dma_addr_to_virt() > - in the new PCI DMA mapping interface to replace > - bus_to_virt() or else this code is going to become very > - innefficient. > - */ > - struct blogic_ccb *ccb = > - (struct blogic_ccb *) bus_to_virt(next_inbox->ccb); > - if (comp_code != BLOGIC_CMD_NOTFOUND) { > + struct blogic_ccb *ccb = blogic_inbox_to_ccb(adapter, next_inbox); > + if (!ccb) { > + /* > + * This should never happen, unless the CCB list is > + * corrupted in memory. > + */ > + blogic_warn("Could not find CCB for dma address %x\n", adapter, next_inbox->ccb); > + } else if (comp_code != BLOGIC_CMD_NOTFOUND) { > if (ccb->status == BLOGIC_CCB_ACTIVE || > ccb->status == BLOGIC_CCB_RESET) { > /* > diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig > index 6e3a04107bb6..689186f3a908 100644 > --- a/drivers/scsi/Kconfig > +++ b/drivers/scsi/Kconfig > @@ -514,7 +514,7 @@ config SCSI_HPTIOP > > config SCSI_BUSLOGIC > tristate "BusLogic SCSI support" > - depends on PCI && SCSI && VIRT_TO_BUS > + depends on PCI && SCSI > help > This is support for BusLogic MultiMaster and FlashPoint SCSI Host > Adapters. Consult the SCSI-HOWTO, available from
diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c index a897c8f914cf..f2abffce2659 100644 --- a/drivers/scsi/BusLogic.c +++ b/drivers/scsi/BusLogic.c @@ -2515,12 +2515,26 @@ static int blogic_resultcode(struct blogic_adapter *adapter, return (hoststatus << 16) | tgt_status; } +/* + * turn the dma address from an inbox into a ccb pointer + * This is rather inefficient. + */ +static struct blogic_ccb * +blogic_inbox_to_ccb(struct blogic_adapter *adapter, struct blogic_inbox *inbox) +{ + struct blogic_ccb *ccb; + + for (ccb = adapter->all_ccbs; ccb; ccb = ccb->next_all) + if (inbox->ccb == ccb->dma_handle) + break; + + return ccb; +} /* blogic_scan_inbox scans the Incoming Mailboxes saving any Incoming Mailbox entries for completion processing. */ - static void blogic_scan_inbox(struct blogic_adapter *adapter) { /* @@ -2540,17 +2554,14 @@ static void blogic_scan_inbox(struct blogic_adapter *adapter) enum blogic_cmplt_code comp_code; while ((comp_code = next_inbox->comp_code) != BLOGIC_INBOX_FREE) { - /* - We are only allowed to do this because we limit our - architectures we run on to machines where bus_to_virt( - actually works. There *needs* to be a dma_addr_to_virt() - in the new PCI DMA mapping interface to replace - bus_to_virt() or else this code is going to become very - innefficient. - */ - struct blogic_ccb *ccb = - (struct blogic_ccb *) bus_to_virt(next_inbox->ccb); - if (comp_code != BLOGIC_CMD_NOTFOUND) { + struct blogic_ccb *ccb = blogic_inbox_to_ccb(adapter, next_inbox); + if (!ccb) { + /* + * This should never happen, unless the CCB list is + * corrupted in memory. + */ + blogic_warn("Could not find CCB for dma address %x\n", adapter, next_inbox->ccb); + } else if (comp_code != BLOGIC_CMD_NOTFOUND) { if (ccb->status == BLOGIC_CCB_ACTIVE || ccb->status == BLOGIC_CCB_RESET) { /* diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig index 6e3a04107bb6..689186f3a908 100644 --- a/drivers/scsi/Kconfig +++ b/drivers/scsi/Kconfig @@ -514,7 +514,7 @@ config SCSI_HPTIOP config SCSI_BUSLOGIC tristate "BusLogic SCSI support" - depends on PCI && SCSI && VIRT_TO_BUS + depends on PCI && SCSI help This is support for BusLogic MultiMaster and FlashPoint SCSI Host Adapters. Consult the SCSI-HOWTO, available from