kernel/linux.git/sound/core/pcm_memory.c, branch linux-6.9.y

ALSA: pcm: Use guard() for locking

2024-02-28T14:01:22+00:00

We can simplify the code gracefully with new guard() macro and co for automatic cleanup of locks. Only the code refactoring, and no functional changes. Signed-off-by: Takashi Iwai Link: https://lore.kernel.org/r/20240227085306.9764-22-tiwai@suse.de

ALSA: pcm: Fix potential data race at PCM memory allocation helpers

2023-07-03T12:52:27+00:00

The PCM memory allocation helpers have a sanity check against too many buffer allocations. However, the check is performed without a proper lock and the allocation isn't serialized; this allows user to allocate more memories than predefined max size. Practically seen, this isn't really a big problem, as it's more or less some "soft limit" as a sanity check, and it's not possible to allocate unlimitedly. But it's still better to address this for more consistent behavior. The patch covers the size check in do_alloc_pages() with the card->memory_mutex, and increases the allocated size there for preventing the further overflow. When the actual allocation fails, the size is decreased accordingly. Reported-by: BassCheck Reported-by: Tuo Li Link: https://lore.kernel.org/r/CADm8Tek6t0WedK+3Y6rbE5YEt19tML8BUL45N2ji4ZAz1KcN_A@mail.gmail.com Reviewed-by: Jaroslav Kysela Cc: Link: https://lore.kernel.org/r/20230703112430.30634-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: pcm: Fix missing return value comments for kernel docs

2022-07-13T11:42:34+00:00

Each kernel doc comment expects the definition of the return value in a proper format. This patch adds or fixes the missing entries for PCM API. Link: https://lore.kernel.org/r/20220713104759.4365-3-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: pcm: Check for null pointer of pointer substream before dereferencing it

2022-04-25T05:52:50+00:00

Pointer substream is being dereferenced on the assignment of pointer card before substream is being null checked with the macro PCM_RUNTIME_CHECK. Although PCM_RUNTIME_CHECK calls BUG_ON, it still is useful to perform the the pointer check before card is assigned. Fixes: d4cfb30fce03 ("ALSA: pcm: Set per-card upper limit of PCM buffer allocations") Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20220424205945.1372247-1-colin.i.king@gmail.com Signed-off-by: Takashi Iwai

ALSA: pcm: Fix races among concurrent prealloc proc writes

2022-03-22T19:56:58+00:00

We have no protection against concurrent PCM buffer preallocation changes via proc files, and it may potentially lead to UAF or some weird problem. This patch applies the PCM open_mutex to the proc write operation for avoiding the racy proc writes and the PCM stream open (and further operations). Cc: Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20220322170720.3529-5-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: memalloc: Support for non-contiguous page allocation

2021-10-18T11:32:10+00:00

This patch adds the support for allocation of non-contiguous DMA pages in the common memalloc helper. It's another SG-buffer type, but unlike the existing one, this is directional and requires the explicit sync / invalidation of dirty pages on non-coherent architectures. For this enhancement, the following points are changed: - snd_dma_device stores the DMA direction. - snd_dma_device stores need_sync flag indicating whether the explicit sync is required or not. - A new variant of helper functions, snd_dma_alloc_dir_pages() and *_all() are introduced; the old snd_dma_alloc_pages() and *_all() kept as just wrappers with DMA_BIDIRECTIONAL. - A new helper snd_dma_buffer_sync() is introduced; this gets called in the appropriate places. - A new allocation type, SNDRV_DMA_TYPE_NONCONTIG, is introduced. When the driver allocates pages with this new type, and it may require the SNDRV_PCM_INFO_EXPLICIT_SYNC flag set to the PCM hardware.info for taking the full control of PCM applptr and hwptr changes (that implies disabling the mmap of control/status data). When the buffer allocation is managed by snd_pcm_set_managed_buffer(), this flag is automatically set depending on the result of dma_need_sync() internally. Otherwise, if the buffer is managed manually, the driver has to set the flag explicitly, too. The explicit sync between CPU and device for non-coherent memory is performed at the points before and after read/write transfer as well as the applptr/hwptr syncptr ioctl. In the case of mmap mode, user-space is supposed to call the syncptr ioctl with the hwptr flag to update and fetch the status at first; this corresponds to CPU-sync. Then user-space advances the applptr via syncptr ioctl again with applptr flag, and this corresponds to the device sync with flushing. Other than the DMA direction and the explicit sync, the usage of this new buffer type is almost equivalent with the existing SNDRV_DMA_TYPE_DEV_SG; you can get the page and the address via snd_sgbuf_get_page() and snd_sgbuf_get_addr(), also calculate the continuous pages via snd_sgbuf_get_chunk_size(). For those SG-page handling, the non-contig type shares the same ops with the vmalloc handler. As we do always vmap the SG pages at first, the actual address can be deduced from the vmapped address easily without iterating the SG-list. Link: https://lore.kernel.org/r/20211017074859.24112-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: pcm: Allow exact buffer preallocation

2021-08-04T06:08:06+00:00

A few drivers want to have rather the exact buffer preallocation at the driver probe time and keep using it for the whole operations without allowing dynamic buffer allocation. For satisfying the demands, this patch extends the managed buffer allocation API slightly. Namely, when 0 is passed to max argument of the allocation helper functions snd_pcm_set_managed_buffer*(), it treats as if the fixed size allocation of the given size. If the pre-allocation fails in this mode, the function returns now -ENOMEM. Otherwise, i.e. max argument is non-zero, the function never returns -ENOMEM but tries to fall back to the smaller chunks and allows the dynamic allocation later -- which is still the default behavior until now. For more intuitive use, also two new helpers are added for handling the fixed size buffer allocation, too: snd_pcm_set_fixed_buffer() and snd_pcm_set_fixed_buffer_all(). Acked-by: Mark Brown Link: https://lore.kernel.org/r/20210802072815.13551-4-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Abstract memory alloc helpers

2021-06-10T08:15:21+00:00

This patch introduces the ops table to each memory allocation type (SNDRV_DMA_TYPE_XXX) and abstract the handling for the better code management. Then we get separate the page allocation, release and other tasks for each type, especially for the SG buffer. Each buffer type has now callbacks in the struct snd_malloc_ops, and the common helper functions call those ops accordingly. The former inline code that is specific to SG-buffer is moved into the local sgbuf.c, and we can simplify the PCM code without details of memory handling. Link: https://lore.kernel.org/r/20210609162551.7842-4-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: avoid -Wempty-body warnings

2021-03-22T11:26:00+00:00

Building with 'make W=1' shows some warnings about empty function-style macros: sound/core/pcm_memory.c: In function 'preallocate_pages': sound/core/pcm_memory.c:236:49: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body] 236 | preallocate_info_init(substream); sound/core/seq_device.c: In function 'snd_seq_device_dev_register': sound/core/seq_device.c:163:41: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body] 163 | queue_autoload_drivers(); Change them to empty inline functions, which are more robust here. Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20210322103128.547199-1-arnd@kernel.org Signed-off-by: Takashi Iwai

ALSA: pcm: Add debug print on memory allocation failure

2021-03-19T15:54:47+00:00

Add debug prints after calls of do_alloc_pages. One simplification would be to move print into do_alloc_pages, however it would cause spam in logs, as preallocate_pcm_pages loops over do_alloc_pages trying lower values in case of failures. Reviewed-by: Cezary Rojewski Signed-off-by: Amadeusz Sławiński Link: https://lore.kernel.org/r/20210318160618.2504068-2-amadeuszx.slawinski@linux.intel.com Signed-off-by: Takashi Iwai