| Message ID | 20180328135817.2419127-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | nvme: use upper_32_bits() instead of bit shift | expand |
Looks good,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
On Wed, Mar 28, 2018 at 03:57:47PM +0200, Arnd Bergmann wrote: > @@ -2233,8 +2233,8 @@ int nvme_get_log_ext(struct nvme_ctrl *ctrl, struct nvme_ns *ns, > c.get_log_page.lid = log_page; > c.get_log_page.numdl = cpu_to_le16(dwlen & ((1 << 16) - 1)); > c.get_log_page.numdu = cpu_to_le16(dwlen >> 16); > - c.get_log_page.lpol = cpu_to_le32(offset & ((1ULL << 32) - 1)); > - c.get_log_page.lpou = cpu_to_le32(offset >> 32ULL); > + c.get_log_page.lpol = cpu_to_le32(lower_32_bits(offset)); > + c.get_log_page.lpou = cpu_to_le32(upper_32_bits(offset)); > > return nvme_submit_sync_cmd(ctrl->admin_q, &c, log, size); > } Right, Matias posted the same fix here: http://lists.infradead.org/pipermail/linux-nvme/2018-March/016474.html In addition to the type safe shifting, a 64-bit type was used to match the spec.
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 4e4136bfc37f..0a81704b763f 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -2233,8 +2233,8 @@ int nvme_get_log_ext(struct nvme_ctrl *ctrl, struct nvme_ns *ns, c.get_log_page.lid = log_page; c.get_log_page.numdl = cpu_to_le16(dwlen & ((1 << 16) - 1)); c.get_log_page.numdu = cpu_to_le16(dwlen >> 16); - c.get_log_page.lpol = cpu_to_le32(offset & ((1ULL << 32) - 1)); - c.get_log_page.lpou = cpu_to_le32(offset >> 32ULL); + c.get_log_page.lpol = cpu_to_le32(lower_32_bits(offset)); + c.get_log_page.lpou = cpu_to_le32(upper_32_bits(offset)); return nvme_submit_sync_cmd(ctrl->admin_q, &c, log, size); }
On 32-bit architectures, we cannot shift a size_t by 32 bits to the right without a compiler warning: drivers/nvme/host/core.c: In function 'nvme_get_log_ext': drivers/nvme/host/core.c:2237:43: error: right shift count >= width of type [-Werror=shift-count-overflow] c.get_log_page.lpou = cpu_to_le32(offset >> 32ULL); ^~ include/uapi/linux/byteorder/little_endian.h:33:51: note: in definition of macro '__cpu_to_le32' #define __cpu_to_le32(x) ((__force __le32)(__u32)(x)) ^ drivers/nvme/host/core.c:2237:24: note: in expansion of macro 'cpu_to_le32' c.get_log_page.lpou = cpu_to_le32(offset >> 32ULL); The code is correct, but using the upper_32_bits() and lower_32_bits() macros that were introduced for this operation makes it easier to read and avoids the warning. Fixes: 70da6094a646 ("nvme: implement log page low/high offset and dwords") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/nvme/host/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 2.9.0