linux-kernel - [PATCH] IB/iser: use sector_div instead of do

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Date:	Fri, 20 Nov 2015 17:41:36 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Or Gerlitz <ogerlitz@...lanox.com>,
	Sagi Grimberg <sagig@...lanox.com>
Cc:	nico@...xnic.net, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, Roi Dayan <roid@...lanox.com>,
	Doug Ledford <dledford@...hat.com>,
	Sean Hefty <sean.hefty@...el.com>,
	Hal Rosenstock <hal.rosenstock@...il.com>,
	linux-rdma@...r.kernel.org
Subject: [PATCH] IB/iser: use sector_div instead of do_div

do_div is the wrong way to divide a sector_t, as it is less
efficient when sector_t is 32-bit wide. With the upcoming
do_div optimizations, the kernel starts warning about this:

drivers/infiniband/ulp/iser/iser_verbs.c:1296:4: note: in expansion of macro 'do_div'
include/asm-generic/div64.h:224:22: warning: passing argument 1 of '__div64_32' from incompatible pointer type

This changes the code to use sector_div instead, which always
produces optimal code.

Signed-off-by: Arnd Bergmann <arnd@...db.de>

diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index a93070210109..42f4da620f2e 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -1293,7 +1293,7 @@ u8 iser_check_task_pi_status(struct iscsi_iser_task *iser_task,
 		if (mr_status.fail_status & IB_MR_CHECK_SIG_STATUS) {
 			sector_t sector_off = mr_status.sig_err.sig_err_offset;
 
-			do_div(sector_off, sector_size + 8);
+			sector_div(sector_off, sector_size + 8);
 			*sector = scsi_get_lba(iser_task->sc) + sector_off;
 
 			pr_err("PI error found type %d at sector %llx "

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