Kemeng Shi c9ba5249ef Xarray: move forward index correctly in xas_pause()
After xas_load(), xas->index could point to mid of found multi-index entry
and xas->index's bits under node->shift maybe non-zero.  The afterward
xas_pause() will move forward xas->index with xa->node->shift with bits
under node->shift un-masked and thus skip some index unexpectedly.

Consider following case:
Assume XA_CHUNK_SHIFT is 4.
xa_store_range(xa, 16, 31, ...)
xa_store(xa, 32, ...)
XA_STATE(xas, xa, 17);
xas_for_each(&xas,...)
xas_load(&xas)
/* xas->index = 17, xas->xa_offset = 1, xas->xa_node->xa_shift = 4 */
xas_pause()
/* xas->index = 33, xas->xa_offset = 2, xas->xa_node->xa_shift = 4 */
As we can see, index of 32 is skipped unexpectedly.

Fix this by mask bit under node->xa_shift when move forward index in
xas_pause().

For now, this will not cause serious problems.  Only minor problem like
cachestat return less number of page status could happen.

Link: https://lkml.kernel.org/r/20241213122523.12764-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Mattew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-24 22:47:27 -08:00
2024-09-01 20:43:24 -07:00
…
2025-01-24 22:47:25 -08:00
…
2025-01-05 14:13:40 -08:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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