posix: simplify read and pread functions

[GBuella]

This change is 

[codecov-io]

Codecov Report

Merging #299 into master will decrease coverage by 0.06%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #299      +/-   ##
==========================================
- Coverage    79.4%   79.33%   -0.07%     
==========================================
  Files          81       81              
  Lines       12127    12096      -31     
  Branches     1642     1636       -6     
==========================================
- Hits         9629     9596      -33     
  Misses       1891     1891              
- Partials      607      609       +2

Impacted Files	Coverage Δ
src/libpmemfile-posix/read.c	92.85% <100%> (-0.23%)	:arrow_down:
tests/posix/mt/mt.cpp	85.41% <0%> (-1.05%)	:arrow_down:
src/libpmemfile-posix/rename.c	91.12% <0%> (-0.41%)	:arrow_down:
src/libpmemfile-posix/file.c	65.93% <0%> (-0.28%)	:arrow_down:
src/libpmemfile-posix/dir.c	82.06% <0%> (+0.04%)	:arrow_up:
src/libpmemfile-posix/utils.c	73.43% <0%> (+0.42%)	:arrow_up:

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[krzycz]

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Reviewed 1 of 1 files at r1. Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[marcinslusarz]

Review status: all files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

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src/libpmemfile-posix/read.c, line 220 at r1 (raw file):

pmemfile_read(PMEMfilepool *pfp, PMEMfile *file, void *buf, size_t count)
{
  return pmemfile_readv(pfp, file, &(pmemfile_iovec_t) {buf, count}, 1);

local variable please

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src/libpmemfile-posix/read.c, line 260 at r1 (raw file):

{
  return pmemfile_preadv(pfp, file,
          &(pmemfile_iovec_t) {buf, count}, 1, offset);

and here

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Comments from Reviewable

[GBuella]

Review status: 0 of 1 files reviewed at latest revision, 2 unresolved discussions.

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src/libpmemfile-posix/read.c, line 220 at r1 (raw file):

Previously, marcinslusarz (Marcin Ślusarz) wrote…

local variable please

Done.

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src/libpmemfile-posix/read.c, line 260 at r1 (raw file):

Previously, marcinslusarz (Marcin Ślusarz) wrote…

and here

Done.

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Comments from Reviewable

[marcinslusarz]

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Reviewed 1 of 1 files at r2. Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[sarahjelinek]

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Reviewed 1 of 1 files at r2. Review status: :shipit: all files reviewed at latest revision, all discussions resolved, all commit checks successful.

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Comments from Reviewable