kernel/linux.git/include/linux/bitmap.h, branch v5.10.240

fix bitmap corruption on close_range() with CLOSE_RANGE_UNSHARE

2024-09-04T11:17:30+00:00

commit 9a2fa1472083580b6c66bdaf291f591e1170123a upstream. copy_fd_bitmaps(new, old, count) is expected to copy the first count/BITS_PER_LONG bits from old->full_fds_bits[] and fill the rest with zeroes. What it does is copying enough words (BITS_TO_LONGS(count/BITS_PER_LONG)), then memsets the rest. That works fine, *if* all bits past the cutoff point are clear. Otherwise we are risking garbage from the last word we'd copied. For most of the callers that is true - expand_fdtable() has count equal to old->max_fds, so there's no open descriptors past count, let alone fully occupied words in ->open_fds[], which is what bits in ->full_fds_bits[] correspond to. The other caller (dup_fd()) passes sane_fdtable_size(old_fdt, max_fds), which is the smallest multiple of BITS_PER_LONG that covers all opened descriptors below max_fds. In the common case (copying on fork()) max_fds is ~0U, so all opened descriptors will be below it and we are fine, by the same reasons why the call in expand_fdtable() is safe. Unfortunately, there is a case where max_fds is less than that and where we might, indeed, end up with junk in ->full_fds_bits[] - close_range(from, to, CLOSE_RANGE_UNSHARE) with * descriptor table being currently shared * 'to' being above the current capacity of descriptor table * 'from' being just under some chunk of opened descriptors. In that case we end up with observably wrong behaviour - e.g. spawn a child with CLONE_FILES, get all descriptors in range 0..127 open, then close_range(64, ~0U, CLOSE_RANGE_UNSHARE) and watch dup(0) ending up with descriptor #128, despite #64 being observably not open. The minimally invasive fix would be to deal with that in dup_fd(). If this proves to add measurable overhead, we can go that way, but let's try to fix copy_fd_bitmaps() first. * new helper: bitmap_copy_and_expand(to, from, bits_to_copy, size). * make copy_fd_bitmaps() take the bitmap size in words, rather than bits; it's 'count' argument is always a multiple of BITS_PER_LONG, so we are not losing any information, and that way we can use the same helper for all three bitmaps - compiler will see that count is a multiple of BITS_PER_LONG for the large ones, so it'll generate plain memcpy()+memset(). Reproducer added to tools/testing/selftests/core/close_range_test.c Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

bitmap: introduce generic optimized bitmap_size()

2024-09-04T11:17:30+00:00

commit a37fbe666c016fd89e4460d0ebfcea05baba46dc upstream. The number of times yet another open coded `BITS_TO_LONGS(nbits) * sizeof(long)` can be spotted is huge. Some generic helper is long overdue. Add one, bitmap_size(), but with one detail. BITS_TO_LONGS() uses DIV_ROUND_UP(). The latter works well when both divident and divisor are compile-time constants or when the divisor is not a pow-of-2. When it is however, the compilers sometimes tend to generate suboptimal code (GCC 13): 48 83 c0 3f add $0x3f,%rax 48 c1 e8 06 shr $0x6,%rax 48 8d 14 c5 00 00 00 00 lea 0x0(,%rax,8),%rdx %BITS_PER_LONG is always a pow-2 (either 32 or 64), but GCC still does full division of `nbits + 63` by it and then multiplication by 8. Instead of BITS_TO_LONGS(), use ALIGN() and then divide by 8. GCC: 8d 50 3f lea 0x3f(%rax),%edx c1 ea 03 shr $0x3,%edx 81 e2 f8 ff ff 1f and $0x1ffffff8,%edx Now it shifts `nbits + 63` by 3 positions (IOW performs fast division by 8) and then masks bits[2:0]. bloat-o-meter: add/remove: 0/0 grow/shrink: 20/133 up/down: 156/-773 (-617) Clang does it better and generates the same code before/after starting from -O1, except that with the ALIGN() approach it uses %edx and thus still saves some bytes: add/remove: 0/0 grow/shrink: 9/133 up/down: 18/-538 (-520) Note that we can't expand DIV_ROUND_UP() by adding a check and using this approach there, as it's used in array declarations where expressions are not allowed. Add this helper to tools/ as well. Reviewed-by: Przemek Kitszel Acked-by: Yury Norov Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

lib: bitmap: provide devm_bitmap_alloc() and devm_bitmap_zalloc()

2022-08-21T13:15:45+00:00

[ Upstream commit e829c2e4744850bab4d8f8ffebd00df10b4c6c2b ] Provide managed variants of bitmap_alloc() and bitmap_zalloc(). Signed-off-by: Bartosz Golaszewski Reviewed-by: Andy Shevchenko Signed-off-by: Sasha Levin

lib: bitmap: order includes alphabetically

2022-08-21T13:15:45+00:00

[ Upstream commit c13656b904b6173aad723d9680a81c60de2f5edc ] For better readability and maintenance: order the includes in bitmap source files alphabetically. Signed-off-by: Bartosz Golaszewski Reviewed-by: Andy Shevchenko Signed-off-by: Sasha Levin

include/bitmap.h: add new functions to documentation

2020-03-05T21:23:25+00:00

I found these functions only by chance although I was looking exactly for something like them. So, add them to the list of functions to make them more visible. Fixes: e837dfde15a4 ("bitmap: genericize percpu bitmap region iterators") Signed-off-by: Wolfram Sang Signed-off-by: Dennis Zhou

include/bitmap.h: add missing parameter in docs

2020-03-05T21:12:54+00:00

bitmap_find_next_zero_area_off() has an additional parameter which was not specified in the list of functions. Add it. Fixes: 5e19b013f55a ("lib: bitmap: add alignment offset for bitmap_find_next_zero_area()") Signed-off-by: Wolfram Sang Signed-off-by: Dennis Zhou

lib: rework bitmap_parse()

2020-02-04T03:05:26+00:00

bitmap_parse() is ineffective and full of opaque variables and opencoded parts. It leads to hard understanding and usage of it. This rework includes: - remove bitmap_shift_left() call from the cycle. Now it makes the complexity of the algorithm as O(nbits^2). In the suggested approach the input string is parsed in reverse direction, so no shifts needed; - relax requirement on a single comma and no white spaces between chunks. It is considered useful in scripting, and it aligns with bitmap_parselist(); - split bitmap_parse() to small readable helpers; - make an explicit calculation of the end of input line at the beginning, so users of the bitmap_parse() won't bother doing this. Link: http://lkml.kernel.org/r/20200102043031.30357-6-yury.norov@gmail.com Signed-off-by: Yury Norov Cc: Amritha Nambiar Cc: Andy Shevchenko Cc: Arnaldo Carvalho de Melo Cc: Chris Wilson Cc: Kees Cook Cc: Matthew Wilcox Cc: Miklos Szeredi Cc: Rasmus Villemoes Cc: Steffen Klassert Cc: "Tobin C . Harding" Cc: Vineet Gupta Cc: Will Deacon Cc: Willem de Bruijn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

2020-01-29T00:02:33+00:00

Pull networking updates from David Miller: 1) Add WireGuard 2) Add HE and TWT support to ath11k driver, from John Crispin. 3) Add ESP in TCP encapsulation support, from Sabrina Dubroca. 4) Add variable window congestion control to TIPC, from Jon Maloy. 5) Add BCM84881 PHY driver, from Russell King. 6) Start adding netlink support for ethtool operations, from Michal Kubecek. 7) Add XDP drop and TX action support to ena driver, from Sameeh Jubran. 8) Add new ipv4 route notifications so that mlxsw driver does not have to handle identical routes itself. From Ido Schimmel. 9) Add BPF dynamic program extensions, from Alexei Starovoitov. 10) Support RX and TX timestamping in igc, from Vinicius Costa Gomes. 11) Add support for macsec HW offloading, from Antoine Tenart. 12) Add initial support for MPTCP protocol, from Christoph Paasch, Matthieu Baerts, Florian Westphal, Peter Krystad, and many others. 13) Add Octeontx2 PF support, from Sunil Goutham, Geetha sowjanya, Linu Cherian, and others. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1469 commits) net: phy: add default ARCH_BCM_IPROC for MDIO_BCM_IPROC udp: segment looped gso packets correctly netem: change mailing list qed: FW 8.42.2.0 debug features qed: rt init valid initialization changed qed: Debug feature: ilt and mdump qed: FW 8.42.2.0 Add fw overlay feature qed: FW 8.42.2.0 HSI changes qed: FW 8.42.2.0 iscsi/fcoe changes qed: Add abstraction for different hsi values per chip qed: FW 8.42.2.0 Additional ll2 type qed: Use dmae to write to widebus registers in fw_funcs qed: FW 8.42.2.0 Parser offsets modified qed: FW 8.42.2.0 Queue Manager changes qed: FW 8.42.2.0 Expose new registers and change windows qed: FW 8.42.2.0 Internal ram offsets modifications MAINTAINERS: Add entry for Marvell OcteonTX2 Physical Function driver Documentation: net: octeontx2: Add RVU HW and drivers overview octeontx2-pf: ethtool RSS config support octeontx2-pf: Add basic ethtool support ...

bitmap: Introduce bitmap_cut(): cut bits and shift remaining

2020-01-27T07:54:30+00:00

The new bitmap function bitmap_cut() copies bits from source to destination by removing the region specified by parameters first and cut, and remapping the bits above the cut region by right shifting them. Signed-off-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso

bitmap: genericize percpu bitmap region iterators

2020-01-20T15:40:56+00:00

Bitmaps are fairly popular for their space efficiency, but we don't have generic iterators available. Make percpu's bitmap region iterators available to everyone. Reviewed-by: Josef Bacik Signed-off-by: Dennis Zhou Reviewed-by: David Sterba Signed-off-by: David Sterba