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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /Documentation/admin-guide/device-mapper/kcopyd.rst | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'Documentation/admin-guide/device-mapper/kcopyd.rst')
| -rw-r--r-- | Documentation/admin-guide/device-mapper/kcopyd.rst | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/kcopyd.rst b/Documentation/admin-guide/device-mapper/kcopyd.rst new file mode 100644 index 000000000..7651d3951 --- /dev/null +++ b/Documentation/admin-guide/device-mapper/kcopyd.rst @@ -0,0 +1,47 @@ +====== +kcopyd +====== + +Kcopyd provides the ability to copy a range of sectors from one block-device +to one or more other block-devices, with an asynchronous completion +notification. It is used by dm-snapshot and dm-mirror. + +Users of kcopyd must first create a client and indicate how many memory pages +to set aside for their copy jobs. This is done with a call to +kcopyd_client_create():: + + int kcopyd_client_create(unsigned int num_pages, + struct kcopyd_client **result); + +To start a copy job, the user must set up io_region structures to describe +the source and destinations of the copy. Each io_region indicates a +block-device along with the starting sector and size of the region. The source +of the copy is given as one io_region structure, and the destinations of the +copy are given as an array of io_region structures:: + + struct io_region { + struct block_device *bdev; + sector_t sector; + sector_t count; + }; + +To start the copy, the user calls kcopyd_copy(), passing in the client +pointer, pointers to the source and destination io_regions, the name of a +completion callback routine, and a pointer to some context data for the copy:: + + int kcopyd_copy(struct kcopyd_client *kc, struct io_region *from, + unsigned int num_dests, struct io_region *dests, + unsigned int flags, kcopyd_notify_fn fn, void *context); + + typedef void (*kcopyd_notify_fn)(int read_err, unsigned int write_err, + void *context); + +When the copy completes, kcopyd will call the user's completion routine, +passing back the user's context pointer. It will also indicate if a read or +write error occurred during the copy. + +When a user is done with all their copy jobs, they should call +kcopyd_client_destroy() to delete the kcopyd client, which will release the +associated memory pages:: + + void kcopyd_client_destroy(struct kcopyd_client *kc); |
