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Groups > linux.kernel > #1360114

[PATCH 3/8] lib/mpi: mpi_write_sgl(): purge redundant pointer arithmetic

From Nicolai Stange <nicstange@gmail.com>
Newsgroups linux.kernel
Subject [PATCH 3/8] lib/mpi: mpi_write_sgl(): purge redundant pointer arithmetic
Date 2016-03-17 19:10 +0100
Message-ID <rdKwY-2ml-41@gated-at.bofh.it> (permalink)
References <rdKwX-2ml-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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

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Thread

[PATCH 0/8] lib/mpi: bug fixes and cleanup Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 8/8] lib/mpi: mpi_read_buffer(): fix buffer overflow Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 2/8] lib/mpi: mpi_write_sgl(): fix style issue with lzero decrement Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 5/8] lib/mpi: mpi_write_sgl(): replace open coded endian conversion Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 1/8] lib/mpi: mpi_write_sgl(): fix skipping of leading zero limbs Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 4/8] lib/mpi: mpi_write_sgl(): fix out-of-bounds stack access Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 3/8] lib/mpi: mpi_write_sgl(): purge redundant pointer arithmetic Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  [PATCH 6/8] lib/mpi: mpi_read_buffer(): optimize skipping of leading zero limbs Nicolai Stange <nicstange@gmail.com> - 2016-03-17 19:10 +0100
  Re: [PATCH 0/8] lib/mpi: bug fixes and cleanup Nicolai Stange <nicstange@gmail.com> - 2016-03-20 13:50 +0100

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