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| author | Sang-Heon Jeon <ekffu200098@gmail.com> | 2026-08-24 01:18:14 +0900 |
|---|---|---|
| committer | Julia Lawall <Julia.Lawall@inria.fr> | 2026-08-23 22:12:11 +0200 |
| commit | 2bd30b8dc75b823dd7bbef9d7bc68e1fd7ecee5c (patch) | |
| tree | dcc4da1d99f17541c5590ac63c77da4bf372a4ab /Documentation/userspace-api/ioctl/ioctl-decoding.rst | |
| download | linux-stable-2bd30b8dc75b823dd7bbef9d7bc68e1fd7ecee5c.tar.gz linux-stable-2bd30b8dc75b823dd7bbef9d7bc68e1fd7ecee5c.zip | |
coccinelle: alloc_cast: drop removed allocatorsgrafted
- pci_alloc_consistent() and pci_zalloc_consistent() were removed by
commit 7968778914e5
("PCI: Remove the deprecated "pci-dma-compat.h" API")
- kmem_alloc() was removed by commit f078d4ea8276
("xfs: convert kmem_alloc() to kmalloc()")
- kmem_zalloc() was removed by commit 10634530f7ba
("xfs: convert kmem_zalloc() to kzalloc()")
- kmem_zone_alloc() and kmem_zone_zalloc() were removed by commit
bae633a4a283 ("xfs: remove xfs_zone_{alloc,zalloc} helpers")
So drop them from the rules.
No functional change.
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Diffstat (limited to 'Documentation/userspace-api/ioctl/ioctl-decoding.rst')
| -rw-r--r-- | Documentation/userspace-api/ioctl/ioctl-decoding.rst | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/userspace-api/ioctl/ioctl-decoding.rst b/Documentation/userspace-api/ioctl/ioctl-decoding.rst new file mode 100644 index 000000000..380d6bb3e --- /dev/null +++ b/Documentation/userspace-api/ioctl/ioctl-decoding.rst @@ -0,0 +1,31 @@ +============================== +Decoding an IOCTL Magic Number +============================== + +To decode a hex IOCTL code: + +Most architectures use this generic format, but check +include/ARCH/ioctl.h for specifics, e.g. powerpc +uses 3 bits to encode read/write and 13 bits for size. + + ====== ================================== + bits meaning + ====== ================================== + 31-30 00 - no parameters: uses _IO macro + 10 - read: _IOR + 01 - write: _IOW + 11 - read/write: _IOWR + + 29-16 size of arguments + + 15-8 ascii character supposedly + unique to each driver + + 7-0 function # + ====== ================================== + + +So for example 0x82187201 is a read with arg length of 0x218, +character 'r' function 1. Grepping the source reveals this is:: + + #define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct dirent [2]) |
