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Message-ID: <64865e62-ba07-44fd-81a9-8e86447b0f2c@vivo.com>
Date: Fri, 13 Sep 2024 14:33:15 +0800
From: Huan Yang <link@...o.com>
To: "Kasireddy, Vivek" <vivek.kasireddy@...el.com>,
Sumit Semwal <sumit.semwal@...aro.org>,
Christian König <christian.koenig@....com>,
Gerd Hoffmann <kraxel@...hat.com>,
"linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
"linaro-mm-sig@...ts.linaro.org" <linaro-mm-sig@...ts.linaro.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc: "opensource.kernel@...o.com" <opensource.kernel@...o.com>
Subject: Re: [PATCH v6 4/7] udmabuf: udmabuf_create pin folio codestyle
cleanup
在 2024/9/13 6:43, Kasireddy, Vivek 写道:
> Hi Huan,
>
>> Subject: [PATCH v6 4/7] udmabuf: udmabuf_create pin folio codestyle
>> cleanup
>>
>> This patch aims to simplify the pinning of folio during the udmabuf
>> creation. No functional changes.
>>
>> This patch moves the memfd pin folio to udmabuf_pin_folios and modifies
>> the original loop condition, using the pinned folio as the external
>> loop condition, and sets the offset and folio during the traversal process.
>>
>> By this, more readable.
>>
>> Suggested-by: Vivek Kasireddy <vivek.kasireddy@...el.com>
>> Signed-off-by: Huan Yang <link@...o.com>
>> ---
>> drivers/dma-buf/udmabuf.c | 134 +++++++++++++++++++++-----------------
>> 1 file changed, 76 insertions(+), 58 deletions(-)
>>
>> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
>> index aa182a9dcdfa..fe1466f7d55a 100644
>> --- a/drivers/dma-buf/udmabuf.c
>> +++ b/drivers/dma-buf/udmabuf.c
>> @@ -328,17 +328,68 @@ static int export_udmabuf(struct udmabuf *ubuf,
>> return dma_buf_fd(buf, flags);
>> }
>>
>> +static long udmabuf_pin_folios(struct udmabuf *ubuf, struct file *memfd,
>> + loff_t start, loff_t size)
>> +{
>> + pgoff_t pgoff, pgcnt, upgcnt = ubuf->pagecount;
>> + struct folio **folios = NULL;
>> + u32 cur_folio, cur_pgcnt;
>> + long nr_folios;
>> + long ret = 0;
>> + loff_t end;
>> +
>> + pgcnt = size >> PAGE_SHIFT;
>> + folios = kvmalloc_array(pgcnt, sizeof(*folios), GFP_KERNEL);
>> + if (!folios)
>> + return -ENOMEM;
>> +
>> + end = start + (pgcnt << PAGE_SHIFT) - 1;
>> + nr_folios = memfd_pin_folios(memfd, start, end, folios, pgcnt,
>> &pgoff);
>> + if (nr_folios <= 0) {
>> + ret = nr_folios ? nr_folios : -EINVAL;
>> + goto end;
>> + }
>> +
>> + cur_pgcnt = 0;
>> + for (cur_folio = 0; cur_folio < nr_folios; ++cur_folio) {
>> + pgoff_t subpgoff = pgoff;
>> + size_t fsize = folio_size(folios[cur_folio]);
>> +
>> + ret = add_to_unpin_list(&ubuf->unpin_list, folios[cur_folio]);
>> + if (ret < 0)
>> + goto end;
>> +
>> + for (; subpgoff < fsize; subpgoff += PAGE_SIZE) {
>> + ubuf->folios[upgcnt] = folios[cur_folio];
>> + ubuf->offsets[upgcnt] = subpgoff;
>> + ++upgcnt;
>> +
>> + if (++cur_pgcnt >= pgcnt)
>> + goto end;
>> + }
>> +
>> + /**
>> + * In a given range, only the first subpage of the first folio
>> + * has an offset, that is returned by memfd_pin_folios().
>> + * The first subpages of other folios (in the range) have an
>> + * offset of 0.
>> + */
>> + pgoff = 0;
>> + }
>> +end:
>> + ubuf->pagecount = upgcnt;
>> + kvfree(folios);
>> + return ret;
>> +}
>> +
>> static long udmabuf_create(struct miscdevice *device,
>> struct udmabuf_create_list *head,
>> struct udmabuf_create_item *list)
>> {
>> - pgoff_t pgoff, pgcnt, pglimit, pgbuf = 0;
>> - long nr_folios, ret = -EINVAL;
>> - struct file *memfd = NULL;
>> - struct folio **folios;
>> + pgoff_t pgcnt = 0, pglimit;
>> struct udmabuf *ubuf;
>> - u32 i, j, k, flags;
>> - loff_t end;
>> + long ret = -EINVAL;
>> + u32 i, flags;
>>
>> ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);
>> if (!ubuf)
>> @@ -347,81 +398,50 @@ static long udmabuf_create(struct miscdevice
>> *device,
>> INIT_LIST_HEAD(&ubuf->unpin_list);
>> pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;
>> for (i = 0; i < head->count; i++) {
>> - if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
>> + if (!PAGE_ALIGNED(list[i].offset))
>> goto err;
>> - if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
>> + if (!PAGE_ALIGNED(list[i].size))
>> goto err;
>> - ubuf->pagecount += list[i].size >> PAGE_SHIFT;
>> - if (ubuf->pagecount > pglimit)
>> +
>> + pgcnt += list[i].size >> PAGE_SHIFT;
>> + if (pgcnt > pglimit)
>> goto err;
>> }
>>
>> - if (!ubuf->pagecount)
>> + if (!pgcnt)
>> goto err;
>>
>> - ubuf->folios = kvmalloc_array(ubuf->pagecount, sizeof(*ubuf-
>>> folios),
>> - GFP_KERNEL);
>> + ubuf->folios = kvmalloc_array(pgcnt, sizeof(*ubuf->folios),
>> GFP_KERNEL);
>> if (!ubuf->folios) {
>> ret = -ENOMEM;
>> goto err;
>> }
>> - ubuf->offsets = kvcalloc(ubuf->pagecount, sizeof(*ubuf->offsets),
>> - GFP_KERNEL);
>> +
>> + ubuf->offsets = kvcalloc(pgcnt, sizeof(*ubuf->offsets), GFP_KERNEL);
>> if (!ubuf->offsets) {
>> ret = -ENOMEM;
>> goto err;
>> }
>>
>> - pgbuf = 0;
>> for (i = 0; i < head->count; i++) {
>> - memfd = fget(list[i].memfd);
>> - ret = check_memfd_seals(memfd);
>> - if (ret < 0)
>> - goto err;
>> + struct file *memfd = fget(list[i].memfd);
>>
>> - pgcnt = list[i].size >> PAGE_SHIFT;
>> - folios = kvmalloc_array(pgcnt, sizeof(*folios), GFP_KERNEL);
>> - if (!folios) {
>> - ret = -ENOMEM;
>> + if (!memfd) {
>> + ret = -EBADFD;
> Nit: with the above change added, please remove the redundant if (!memfd)
> check from check_memfd_seals().
Yes, right, I'll do it.
Thank you.
>
> Acked-by: Vivek Kasireddy <vivek.kasireddy@...el.com>
>
>> goto err;
>> }
>>
>> - end = list[i].offset + (pgcnt << PAGE_SHIFT) - 1;
>> - ret = memfd_pin_folios(memfd, list[i].offset, end,
>> - folios, pgcnt, &pgoff);
>> - if (ret <= 0) {
>> - kvfree(folios);
>> - if (!ret)
>> - ret = -EINVAL;
>> + ret = check_memfd_seals(memfd);
>> + if (ret < 0) {
>> + fput(memfd);
>> goto err;
>> }
>>
>> - nr_folios = ret;
>> - pgoff >>= PAGE_SHIFT;
>> - for (j = 0, k = 0; j < pgcnt; j++) {
>> - ubuf->folios[pgbuf] = folios[k];
>> - ubuf->offsets[pgbuf] = pgoff << PAGE_SHIFT;
>> -
>> - if (j == 0 || ubuf->folios[pgbuf-1] != folios[k]) {
>> - ret = add_to_unpin_list(&ubuf->unpin_list,
>> - folios[k]);
>> - if (ret < 0) {
>> - kfree(folios);
>> - goto err;
>> - }
>> - }
>> -
>> - pgbuf++;
>> - if (++pgoff == folio_nr_pages(folios[k])) {
>> - pgoff = 0;
>> - if (++k == nr_folios)
>> - break;
>> - }
>> - }
>> -
>> - kvfree(folios);
>> + ret = udmabuf_pin_folios(ubuf, memfd, list[i].offset,
>> + list[i].size);
>> fput(memfd);
>> - memfd = NULL;
>> + if (ret)
>> + goto err;
>> }
>>
>> flags = head->flags & UDMABUF_FLAGS_CLOEXEC ? O_CLOEXEC : 0;
>> @@ -432,8 +452,6 @@ static long udmabuf_create(struct miscdevice
>> *device,
>> return ret;
>>
>> err:
>> - if (memfd)
>> - fput(memfd);
>> unpin_all_folios(&ubuf->unpin_list);
>> kvfree(ubuf->offsets);
>> kvfree(ubuf->folios);
>> --
>> 2.45.2
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