Update Linux to v5.10.157
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.157.tar.xz
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I7b30d9e98d8c465d6b44de8e7433b4a40b3289ba
diff --git a/fs/file.c b/fs/file.c
index 79a76d0..8431dfd 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -85,6 +85,21 @@
copy_fd_bitmaps(nfdt, ofdt, ofdt->max_fds);
}
+/*
+ * Note how the fdtable bitmap allocations very much have to be a multiple of
+ * BITS_PER_LONG. This is not only because we walk those things in chunks of
+ * 'unsigned long' in some places, but simply because that is how the Linux
+ * kernel bitmaps are defined to work: they are not "bits in an array of bytes",
+ * they are very much "bits in an array of unsigned long".
+ *
+ * The ALIGN(nr, BITS_PER_LONG) here is for clarity: since we just multiplied
+ * by that "1024/sizeof(ptr)" before, we already know there are sufficient
+ * clear low bits. Clang seems to realize that, gcc ends up being confused.
+ *
+ * On a 128-bit machine, the ALIGN() would actually matter. In the meantime,
+ * let's consider it documentation (and maybe a test-case for gcc to improve
+ * its code generation ;)
+ */
static struct fdtable * alloc_fdtable(unsigned int nr)
{
struct fdtable *fdt;
@@ -100,6 +115,7 @@
nr /= (1024 / sizeof(struct file *));
nr = roundup_pow_of_two(nr + 1);
nr *= (1024 / sizeof(struct file *));
+ nr = ALIGN(nr, BITS_PER_LONG);
/*
* Note that this can drive nr *below* what we had passed if sysctl_nr_open
* had been set lower between the check in expand_files() and here. Deal
@@ -267,6 +283,19 @@
return i;
}
+/*
+ * Note that a sane fdtable size always has to be a multiple of
+ * BITS_PER_LONG, since we have bitmaps that are sized by this.
+ *
+ * 'max_fds' will normally already be properly aligned, but it
+ * turns out that in the close_range() -> __close_range() ->
+ * unshare_fd() -> dup_fd() -> sane_fdtable_size() we can end
+ * up having a 'max_fds' value that isn't already aligned.
+ *
+ * Rather than make close_range() have to worry about this,
+ * just make that BITS_PER_LONG alignment be part of a sane
+ * fdtable size. Becuase that's really what it is.
+ */
static unsigned int sane_fdtable_size(struct fdtable *fdt, unsigned int max_fds)
{
unsigned int count;
@@ -274,7 +303,7 @@
count = count_open_files(fdt);
if (max_fds < NR_OPEN_DEFAULT)
max_fds = NR_OPEN_DEFAULT;
- return min(count, max_fds);
+ return ALIGN(min(count, max_fds), BITS_PER_LONG);
}
/*