kernel/linux.git/sound/core/memalloc.c, branch v7.0-rc7

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ALSA: memalloc: prefer dma_mapping_error() over explicit address checking

2024-12-20T08:54:12+00:00

With CONFIG_DMA_API_DEBUG enabled, the following warning is observed: DMA-API: snd_hda_intel 0000:03:00.1: device driver failed to check map error[device address=0x00000000ffff0000] [size=20480 bytes] [mapped as single] WARNING: CPU: 28 PID: 2255 at kernel/dma/debug.c:1036 check_unmap+0x1408/0x2430 CPU: 28 UID: 42 PID: 2255 Comm: wireplumber Tainted: G W L 6.12.0-10-133577cad6bf48e5a7848c4338124081393bfe8a+ #759 debug_dma_unmap_page+0xe9/0xf0 snd_dma_wc_free+0x85/0x130 [snd_pcm] snd_pcm_lib_free_pages+0x1e3/0x440 [snd_pcm] snd_pcm_common_ioctl+0x1c9a/0x2960 [snd_pcm] snd_pcm_ioctl+0x6a/0xc0 [snd_pcm] ... Check for returned DMA addresses using specialized dma_mapping_error() helper which is generally recommended for this purpose by Documentation/core-api/dma-api.rst. Fixes: c880a5146642 ("ALSA: memalloc: Use proper DMA mapping API for x86 WC buffer allocations") Reported-by: Mikhail Gavrilov Closes: https://lore.kernel.org/r/CABXGCsNB3RsMGvCucOy3byTEOxoc-Ys+zB_HQ=Opb_GhX1ioDA@mail.gmail.com/ Tested-by: Mikhail Gavrilov Signed-off-by: Fedor Pchelkin Link: https://patch.msgid.link/20241219203345.195898-1-pchelkin@ispras.ru Signed-off-by: Takashi Iwai

ALSA: memalloc: Use proper DMA mapping API for x86 S/G buffer allocations

2024-09-12T16:02:18+00:00

The fallback S/G buffer allocation for x86 used the addresses deduced from the page allocations blindly. It broke the allocations on IOMMU and made us to work around with a hackish DMA ops check. For cleaning up those messes, this patch switches to the proper DMA mapping API usages with the standard sg-table instead. By introducing the sg-table, the address table isn't needed, but for keeping the original allocation sizes for freeing, replace it with the array keeping the number of pages. The get_addr callback is changed to use the existing one for non-contiguous buffers. (Also it's the reason sg_table is put at the beginning of struct snd_dma_sg_fallback.) And finally, the hackish workaround that checks the DMA ops is dropped now. Link: https://patch.msgid.link/20240912155227.4078-3-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Use proper DMA mapping API for x86 WC buffer allocations

2024-09-12T16:02:03+00:00

The x86 WC page allocation assumes incorrectly the DMA address directly taken from the page. Also it checks the DMA ops inappropriately for switching to the own method. This patch rewrites the stuff to use the proper DMA mapping API instead. Link: https://patch.msgid.link/20240912155227.4078-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Drop Xen PV workaround again

2024-09-11T06:31:19+00:00

Since recently in the commit e469e2045f1b ("ALSA: memalloc: Let IOMMU handle S/G primarily"), the SG buffer allocation code was modified to use the standard DMA code primarily and the fallback is applied only limitedly. This made the Xen PV specific workarounds we took in the commit 53466ebdec61 ("ALSA: memalloc: Workaround for Xen PV") rather superfluous. It was a hackish workaround for the regression at that time, and it seems that it's causing another issues (reportedly memory corruptions). So it's better to clean it up, after all. Link: https://lore.kernel.org/20240906184209.25423-1-ariadne@ariadne.space Cc: Ariadne Conill Link: https://patch.msgid.link/20240910113100.32542-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Move snd_malloc_ops definition into memalloc.c again

2024-09-10T11:32:36+00:00

The definition of struct snd_malloc_ops was moved out to memalloc_local.h since there was another code for S/G buffer allocation referring to the struct. But since the code change to use non-contiguous allocators, it's solely referred in memalloc.c, hence it makes little sense to have a separate header file. Let's move it back to memalloc.c. Link: https://patch.msgid.link/20240910113141.32618-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Let IOMMU handle S/G primarily

2024-08-01T10:45:49+00:00

The recent changes in IOMMU made the non-contiguous page allocations as default, hence we can simply use the standard DMA allocation for the S/G pages as well. In this patch, we simplify the code by trying the standard DMA allocation at first, instead of dma_alloc_noncontiguous(). For the case without IOMMU, we still need to manage the S/G pages manually, so we keep the same fallback routines like before. The fallback types (SNDRV_DMA_TYPE_DEV_SG_FALLBACK & co) are dropped / folded into SNDRV_DMA_TYPE_DEV_SG and co now. The allocation via the standard DMA call overrides the type accordingly, hence we don't have to have extra fallback types any longer. OTOH, SNDRV_DMA_TYPE_DEV_SG is no longer an alias but became its own type back again. Note that this patch requires another prerequisite fix for memmalloc helper to use the DMA API for WC pages on x86. Link: https://bugzilla.kernel.org/show_bug.cgi?id=219087 Link: https://patch.msgid.link/20240801064808.31205-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Use DMA API for x86 WC page allocations, too

2024-08-01T10:45:41+00:00

The memalloc helper used a house-made code for allocation of WC pages on x86, since the standard DMA API doesn't cover it well. Meanwhile, the manually allocated pages won't work together with IOMMU, resulting in faults, so we should switch to the DMA API in that case, instead. This patch tries to switch back to DMA API for WC pages on x86, but with some additional tweaks that are missing. Link: https://bugzilla.kernel.org/show_bug.cgi?id=219087 Link: https://patch.msgid.link/20240801064808.31205-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Workaround for Xen PV

2023-01-27T08:16:24+00:00

We change recently the memalloc helper to use dma_alloc_noncontiguous() and the fallback to get_pages(). Although lots of issues with IOMMU (or non-IOMMU) have been addressed, but there seems still a regression on Xen PV. Interestingly, the only proper way to work is use dma_alloc_coherent(). The use of dma_alloc_coherent() for SG buffer was dropped as it's problematic on IOMMU systems. OTOH, Xen PV has a different way, and it's fine to use the dma_alloc_coherent(). This patch is a workaround for Xen PV. It consists of the following changes: - For Xen PV, use only the fallback allocation without dma_alloc_noncontiguous() - In the fallback allocation, use dma_alloc_coherent(); the DMA address from dma_alloc_coherent() is returned in get_addr ops - The DMA addresses are stored in an array; the first entry stores the number of allocated pages in lower bits, which are referred at releasing pages again Reported-by: Marek Marczykowski-Górecki Tested-by: Marek Marczykowski-Górecki Fixes: a8d302a0b770 ("ALSA: memalloc: Revive x86-specific WC page allocations again") Fixes: 9736a325137b ("ALSA: memalloc: Don't fall back for SG-buffer with IOMMU") Link: https://lore.kernel.org/r/87tu256lqs.wl-tiwai@suse.de Link: https://lore.kernel.org/r/20230125153104.5527-1-tiwai@suse.de Signed-off-by: Takashi Iwai