treewide: refresh kmalloc_obj() conversionsgrafted

This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci

This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.

Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.

Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>

1 files changed, 45 insertions, 0 deletions

diff --git a/Documentation/filesystems/fuse/fuse-io.rst b/Documentation/filesystems/fuse/fuse-io.rst
new file mode 100644
index 000000000..d736ac4cb
--- /dev/null
+++ b/Documentation/filesystems/fuse/fuse-io.rst
@@ -0,0 +1,45 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==============
+FUSE I/O Modes
+==============
+
+Fuse supports the following I/O modes:
+
+- direct-io
+- cached
+  + write-through
+  + writeback-cache
+
+The direct-io mode can be selected with the FOPEN_DIRECT_IO flag in the
+FUSE_OPEN reply.
+
+In direct-io mode the page cache is completely bypassed for reads and writes.
+No read-ahead takes place. Shared mmap is disabled by default. To allow shared
+mmap, the FUSE_DIRECT_IO_ALLOW_MMAP flag may be enabled in the FUSE_INIT reply.
+
+In cached mode reads may be satisfied from the page cache, and data may be
+read-ahead by the kernel to fill the cache.  The cache is always kept consistent
+after any writes to the file.  All mmap modes are supported.
+
+The cached mode has two sub modes controlling how writes are handled.  The
+write-through mode is the default and is supported on all kernels.  The
+writeback-cache mode may be selected by the FUSE_WRITEBACK_CACHE flag in the
+FUSE_INIT reply.
+
+In write-through mode each write is immediately sent to userspace as one or more
+WRITE requests, as well as updating any cached pages (and caching previously
+uncached, but fully written pages).  No READ requests are ever sent for writes,
+so when an uncached page is partially written, the page is discarded.
+
+In writeback-cache mode (enabled by the FUSE_WRITEBACK_CACHE flag) writes go to
+the cache only, which means that the write(2) syscall can often complete very
+fast.  Dirty pages are written back implicitly (background writeback or page
+reclaim on memory pressure) or explicitly (invoked by close(2), fsync(2) and
+when the last ref to the file is being released on munmap(2)).  This mode
+assumes that all changes to the filesystem go through the FUSE kernel module
+(size and atime/ctime/mtime attributes are kept up-to-date by the kernel), so
+it's generally not suitable for network filesystems.  If a partial page is
+written, then the page needs to be first read from userspace.  This means, that
+even for files opened for O_WRONLY it is possible that READ requests will be
+generated by the kernel.