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From: Nicolai Stange <nicstange@gmail.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Tadeusz Struk <tadeusz.struk@intel.com>,
	Michal Marek <mmarek@suse.com>,
	Andrzej Zaborowski <andrew.zaborowski@intel.com>,
	Stephan Mueller <smueller@chronox.de>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-kernel@vger.kernel.org,
	Nicolai Stange <nicstange@gmail.com>
Subject: [PATCH 3/8] lib/mpi: mpi_write_sgl(): purge redundant pointer arithmetic
Date: Thu, 17 Mar 2016 19:00:01 +0100	[thread overview]
Message-ID: <1458237606-4954-4-git-send-email-nicstange@gmail.com> (raw)
In-Reply-To: <1458237606-4954-1-git-send-email-nicstange@gmail.com>

Within the copying loop in mpi_write_sgl(), we have

  if (lzeros) {
    ...
    p -= lzeros;
    y = lzeros;
  }
  p = p - (sizeof(alimb) - y);

If lzeros == 0, then y == 0, too. Thus, lzeros gets subtracted and added
back again to p.

Purge this redundancy.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
---
 lib/mpi/mpicoder.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index d8b372b..78ec4e1 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -407,12 +407,11 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes,
 			mpi_limb_t *limb2 = (void *)p - sizeof(alimb)
 				+ lzeros;
 			*limb1 = *limb2;
-			p -= lzeros;
 			y = lzeros;
 			lzeros = 0;
 		}
 
-		p = p - (sizeof(alimb) - y);
+		p = p - sizeof(alimb);
 
 		for (x = 0; x < sizeof(alimb) - y; x++) {
 			if (!buf_len) {
-- 
2.7.2

  parent reply	other threads:[~2016-03-17 18:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-17 17:59 [PATCH 0/8] lib/mpi: bug fixes and cleanup Nicolai Stange
2016-03-17 17:59 ` [PATCH 1/8] lib/mpi: mpi_write_sgl(): fix skipping of leading zero limbs Nicolai Stange
2016-03-17 18:00 ` [PATCH 2/8] lib/mpi: mpi_write_sgl(): fix style issue with lzero decrement Nicolai Stange
2016-03-17 18:00 ` Nicolai Stange [this message]
2016-03-17 18:00 ` [PATCH 4/8] lib/mpi: mpi_write_sgl(): fix out-of-bounds stack access Nicolai Stange
2016-03-17 18:00 ` [PATCH 5/8] lib/mpi: mpi_write_sgl(): replace open coded endian conversion Nicolai Stange
2016-03-17 18:00 ` [PATCH 6/8] lib/mpi: mpi_read_buffer(): optimize skipping of leading zero limbs Nicolai Stange
2016-03-17 18:00 ` [PATCH 7/8] lib/mpi: mpi_read_buffer(): replace open coded endian conversion Nicolai Stange
2016-03-17 18:00 ` [PATCH 8/8] lib/mpi: mpi_read_buffer(): fix buffer overflow Nicolai Stange
2016-03-20 12:40 ` [PATCH 0/8] lib/mpi: bug fixes and cleanup Nicolai Stange

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