kernel/linux.git/lib/reed_solomon, branch v6.12.80

treewide: use get_random_u32_below() instead of deprecated function

2022-11-18T01:15:15+00:00

This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Acked-by: Darrick J. Wong # for xfs Reviewed-by: SeongJae Park # for damon Reviewed-by: Jason Gunthorpe # for infiniband Reviewed-by: Russell King (Oracle) # for arm Acked-by: Ulf Hansson # for mmc Signed-off-by: Jason A. Donenfeld

treewide: use get_random_u32() when possible

2022-10-11T23:42:58+00:00

The prandom_u32() function has been a deprecated inline wrapper around get_random_u32() for several releases now, and compiles down to the exact same code. Replace the deprecated wrapper with a direct call to the real function. The same also applies to get_random_int(), which is just a wrapper around get_random_u32(). This was done as a basic find and replace. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: Jan Kara # for ext4 Acked-by: Toke Høiland-Jørgensen # for sch_cake Acked-by: Chuck Lever # for nfsd Acked-by: Jakub Kicinski Acked-by: Mika Westerberg # for thunderbolt Acked-by: Darrick J. Wong # for xfs Acked-by: Helge Deller # for parisc Acked-by: Heiko Carstens # for s390 Signed-off-by: Jason A. Donenfeld

treewide: use prandom_u32_max() when possible, part 1

2022-10-11T23:42:55+00:00

Rather than incurring a division or requesting too many random bytes for the given range, use the prandom_u32_max() function, which only takes the minimum required bytes from the RNG and avoids divisions. This was done mechanically with this coccinelle script: @basic@ expression E; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u64; @@ ( - ((T)get_random_u32() % (E)) + prandom_u32_max(E) | - ((T)get_random_u32() & ((E) - 1)) + prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2) | - ((u64)(E) * get_random_u32() >> 32) + prandom_u32_max(E) | - ((T)get_random_u32() & ~PAGE_MASK) + prandom_u32_max(PAGE_SIZE) ) @multi_line@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; identifier RAND; expression E; @@ - RAND = get_random_u32(); ... when != RAND - RAND %= (E); + RAND = prandom_u32_max(E); // Find a potential literal @literal_mask@ expression LITERAL; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; position p; @@ ((T)get_random_u32()@p & (LITERAL)) // Add one to the literal. @script:python add_one@ literal << literal_mask.LITERAL; RESULT; @@ value = None if literal.startswith('0x'): value = int(literal, 16) elif literal[0] in '123456789': value = int(literal, 10) if value is None: print("I don't know how to handle %s" % (literal)) cocci.include_match(False) elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1: print("Skipping 0x%x for cleanup elsewhere" % (value)) cocci.include_match(False) elif value & (value + 1) != 0: print("Skipping 0x%x because it's not a power of two minus one" % (value)) cocci.include_match(False) elif literal.startswith('0x'): coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1)) else: coccinelle.RESULT = cocci.make_expr("%d" % (value + 1)) // Replace the literal mask with the calculated result. @plus_one@ expression literal_mask.LITERAL; position literal_mask.p; expression add_one.RESULT; identifier FUNC; @@ - (FUNC()@p & (LITERAL)) + prandom_u32_max(RESULT) @collapse_ret@ type T; identifier VAR; expression E; @@ { - T VAR; - VAR = (E); - return VAR; + return E; } @drop_var@ type T; identifier VAR; @@ { - T VAR; ... when != VAR } Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: KP Singh Reviewed-by: Jan Kara # for ext4 and sbitmap Reviewed-by: Christoph Böhmwalder # for drbd Acked-by: Jakub Kicinski Acked-by: Heiko Carstens # for s390 Acked-by: Ulf Hansson # for mmc Acked-by: Darrick J. Wong # for xfs Signed-off-by: Jason A. Donenfeld

lib: fix spelling mistakes

2021-07-08T18:48:20+00:00

Fix some spelling mistakes in comments: permanentely ==> permanently wont ==> won't remaning ==> remaining succed ==> succeed shouldnt ==> shouldn't alpha-numeric ==> alphanumeric storeing ==> storing funtion ==> function documenation ==> documentation Determin ==> Determine intepreted ==> interpreted ammount ==> amount obious ==> obvious interupts ==> interrupts occured ==> occurred asssociated ==> associated taking into acount ==> taking into account squence ==> sequence stil ==> still contiguos ==> contiguous matchs ==> matches Link: https://lkml.kernel.org/r/20210607072555.12416-1-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei Reviewed-by: Jacob Keller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

rslib: Make some functions static

2019-07-02T06:41:37+00:00

Fix sparse warnings: lib/reed_solomon/test_rslib.c:313:5: warning: symbol 'ex_rs_helper' was not declared. Should it be static? lib/reed_solomon/test_rslib.c:349:5: warning: symbol 'exercise_rs' was not declared. Should it be static? lib/reed_solomon/test_rslib.c:407:5: warning: symbol 'exercise_rs_bc' was not declared. Should it be static? Reported-by: Hulk Robot Signed-off-by: YueHaibing Signed-off-by: Thomas Gleixner Cc: Link: https://lkml.kernel.org/r/20190702061847.26060-1-yuehaibing@huawei.com

rslib: Fix remaining decoder flaws

2019-06-26T12:55:47+00:00

The decoder is flawed in the following ways: - The decoder sometimes fails silently, i.e. it announces success but returns a word that is not a codeword. - The return value of the decoder is incoherent with respect to how fixed erasures are counted. If the word to be decoded is a codeword, then the decoder always returns zero even if some erasures are given. On the other hand, if the word to be decoded contains errors, then the number of erasures is always included in the count of corrected symbols. So the decoder handles erasures without symbol corruption inconsistently. This inconsistency probably doesn't affect anyone using the decoder, but it is inconsistent with the documentation. - The error positions returned in eras_pos include all erasures, but the corrections are only set in the correction buffer if there actually is a symbol error. So if there are erasures without symbol corruption, then the correction buffer will contain errors (unless initialized to zero before calling the decoder) or some values will be unset (if the correction buffer is uninitialized). - When correcting data in-place the decoder does not correct errors in the parity. On the other hand, when returning the errors in correction buffers, errors in the parity are included. The respective fixed are: - The syndrome of a codeword is always zero, and the syndrome is linear, .i.e, S(x+e) = S(x) + S(e). So compute the syndrome for the error and check whether it equals the syndrome of the received word. If it does, then we have decoded to a valid codeword, otherwise we know that we have an uncorrectable error. Fortunately, some unrecoverable error conditions can be detected earlier in the decoding, which saves some processing power. - Simply count and return the number of symbols actually corrected. - Make sure to only return positions where symbols were corrected. - Also fix errors in parity when correcting in-place. Another option would be to completely disregard errors in the parity, but then the interface makes it impossible to write tests that test for silent failures. Other changes: - Only fill the correction buffer and error position buffer if both of them are provided. Otherwise correct in place. Previously the error position buffer was always populated with the positions of the corrected errors, irrespective of whether a correction buffer was supplied or not. The rationale for this change is that there seems to be two use cases for the decoder; correct in-place or use the correction buffers. The caller does not need the positions of the corrected errors when in-place correction is used. If in-place correction is not used, then both the correction buffer and error position buffer need to be populated. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-8-ferdinand.blomqvist@gmail.com

rslib: Update documentation

2019-06-26T12:55:47+00:00

The decoder returns the number of corrected symbols, not bits. The caller provided syndrome must be in index form. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-7-ferdinand.blomqvist@gmail.com

rslib: Fix handling of of caller provided syndrome

2019-06-26T12:55:47+00:00

Check if the syndrome provided by the caller is zero, and act accordingly. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-6-ferdinand.blomqvist@gmail.com

rslib: decode_rs: Code cleanup

2019-06-26T12:55:46+00:00

Nothing useful was done after the finish label when count is negative so return directly instead of jumping to finish. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-5-ferdinand.blomqvist@gmail.com

rslib: decode_rs: Fix length parameter check

2019-06-26T12:55:46+00:00

The length of the data load must be at least one. Or in other words, there must be room for at least 1 data and nroots parity symbols after shortening the RS code. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-4-ferdinand.blomqvist@gmail.com