From patchwork Tue Mar 17 11:56:31 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 28822 X-Patchwork-Delegate: hverkuil@xs4all.nl Received: from mail.tu-berlin.de ([130.149.7.33]) by www.linuxtv.org with esmtp (Exim 4.72) (envelope-from ) id 1YXq7Q-0002Vy-MM; Tue, 17 Mar 2015 12:57:08 +0100 X-tubIT-Incoming-IP: 209.132.180.67 Received: from vger.kernel.org ([209.132.180.67]) by mail.tu-berlin.de (exim-4.76/mailfrontend-8) with esmtp id 1YXq7N-0006dj-lg; Tue, 17 Mar 2015 12:57:07 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754226AbbCQL5C (ORCPT + 1 other); Tue, 17 Mar 2015 07:57:02 -0400 Received: from cantor2.suse.de ([195.135.220.15]:43210 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752959AbbCQL47 (ORCPT ); Tue, 17 Mar 2015 07:56:59 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id A68B0ACF1; Tue, 17 Mar 2015 11:56:57 +0000 (UTC) Received: by quack.suse.cz (Postfix, from userid 1000) id 525B181EF8; Tue, 17 Mar 2015 12:56:53 +0100 (CET) From: Jan Kara To: linux-media@vger.kernel.org Cc: Hans Verkuil , Mauro Carvalho Chehab , linux-mm@kvack.org, dri-devel@lists.freedesktop.org, David Airlie , Jan Kara Subject: [PATCH 1/9] [media] vb2: Push mmap_sem down to memops Date: Tue, 17 Mar 2015 12:56:31 +0100 Message-Id: <1426593399-6549-2-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1426593399-6549-1-git-send-email-jack@suse.cz> References: <1426593399-6549-1-git-send-email-jack@suse.cz> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-PMX-Version: 6.0.0.2142326, Antispam-Engine: 2.7.2.2107409, Antispam-Data: 2015.3.17.115125 X-PMX-Spam: Gauge=IIIIIIII, Probability=8%, Report=' MULTIPLE_RCPTS 0.1, HTML_00_01 0.05, HTML_00_10 0.05, BODY_SIZE_5000_5999 0, BODY_SIZE_7000_LESS 0, REFERENCES 0, URI_ENDS_IN_HTML 0, __ANY_URI 0, __CP_URI_IN_BODY 0, __HAS_FROM 0, __HAS_MSGID 0, __HAS_X_MAILER 0, __HAS_X_MAILING_LIST 0, __IN_REP_TO 0, __MIME_TEXT_ONLY 0, __MULTIPLE_RCPTS_CC_X2 0, __REFERENCES 0, __SANE_MSGID 0, __SUBJ_ALPHA_END 0, __TO_MALFORMED_2 0, __TO_NO_NAME 0, __URI_NO_WWW 0, __URI_NS ' Currently vb2 core acquires mmap_sem just around call to __qbuf_userptr(). However since commit f035eb4e976ef5 (videobuf2: fix lockdep warning) it isn't necessary to acquire it so early as we no longer have to drop queue mutex before acquiring mmap_sem. So push acquisition of mmap_sem down into .get_userptr and .put_userptr memops so that the semaphore is acquired for a shorter time and it is clearer what it is needed for. Signed-off-by: Jan Kara --- drivers/media/v4l2-core/videobuf2-core.c | 2 -- drivers/media/v4l2-core/videobuf2-dma-contig.c | 7 +++++++ drivers/media/v4l2-core/videobuf2-dma-sg.c | 6 ++++++ drivers/media/v4l2-core/videobuf2-vmalloc.c | 6 +++++- 4 files changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index bc08a829bc13..e1fbdecb0b00 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1630,9 +1630,7 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b) ret = __qbuf_mmap(vb, b); break; case V4L2_MEMORY_USERPTR: - down_read(¤t->mm->mmap_sem); ret = __qbuf_userptr(vb, b); - up_read(¤t->mm->mmap_sem); break; case V4L2_MEMORY_DMABUF: ret = __qbuf_dmabuf(vb, b); diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b481d20c8372..96eceabb307b 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -526,7 +526,9 @@ static void vb2_dc_put_userptr(void *buf_priv) sg_free_table(sgt); kfree(sgt); } + down_read(¤t->mm->mmap_sem); vb2_put_vma(buf->vma); + up_read(¤t->mm->mmap_sem); kfree(buf); } @@ -610,6 +612,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, goto fail_buf; } + down_read(¤t->mm->mmap_sem); /* current->mm->mmap_sem is taken by videobuf2 core */ vma = find_vma(current->mm, vaddr); if (!vma) { @@ -637,6 +640,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, if (ret) { unsigned long pfn; if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) { + up_read(¤t->mm->mmap_sem); buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn); buf->size = size; kfree(pages); @@ -646,6 +650,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, pr_err("failed to get user pages\n"); goto fail_vma; } + up_read(¤t->mm->mmap_sem); sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) { @@ -708,10 +713,12 @@ fail_get_user_pages: while (n_pages) put_page(pages[--n_pages]); + down_read(¤t->mm->mmap_sem); fail_vma: vb2_put_vma(buf->vma); fail_pages: + up_read(¤t->mm->mmap_sem); kfree(pages); /* kfree is NULL-proof */ fail_buf: diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c index b1838abb6d00..71510e4f7d7c 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c @@ -263,6 +263,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, if (!buf->pages) goto userptr_fail_alloc_pages; + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, vaddr); if (!vma) { dprintk(1, "no vma for address %lu\n", vaddr); @@ -301,6 +302,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, 1, /* force */ buf->pages, NULL); + up_read(¤t->mm->mmap_sem); if (num_pages_from_user != buf->num_pages) goto userptr_fail_get_user_pages; @@ -328,8 +330,10 @@ userptr_fail_get_user_pages: if (!vma_is_io(buf->vma)) while (--num_pages_from_user >= 0) put_page(buf->pages[num_pages_from_user]); + down_read(¤t->mm->mmap_sem); vb2_put_vma(buf->vma); userptr_fail_find_vma: + up_read(¤t->mm->mmap_sem); kfree(buf->pages); userptr_fail_alloc_pages: kfree(buf); @@ -362,7 +366,9 @@ static void vb2_dma_sg_put_userptr(void *buf_priv) put_page(buf->pages[i]); } kfree(buf->pages); + down_read(¤t->mm->mmap_sem); vb2_put_vma(buf->vma); + up_read(¤t->mm->mmap_sem); kfree(buf); } diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c index bcde88572429..c060cf9662fa 100644 --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c @@ -89,7 +89,7 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr, offset = vaddr & ~PAGE_MASK; buf->size = size; - + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, vaddr); if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) { if (vb2_get_contig_userptr(vaddr, size, &vma, &physp)) @@ -121,6 +121,7 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr, if (!buf->vaddr) goto fail_get_user_pages; } + up_read(¤t->mm->mmap_sem); buf->vaddr += offset; return buf; @@ -133,6 +134,7 @@ fail_get_user_pages: kfree(buf->pages); fail_pages_array_alloc: + up_read(¤t->mm->mmap_sem); kfree(buf); return NULL; @@ -144,6 +146,7 @@ static void vb2_vmalloc_put_userptr(void *buf_priv) unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK; unsigned int i; + down_read(¤t->mm->mmap_sem); if (buf->pages) { if (vaddr) vm_unmap_ram((void *)vaddr, buf->n_pages); @@ -157,6 +160,7 @@ static void vb2_vmalloc_put_userptr(void *buf_priv) vb2_put_vma(buf->vma); iounmap((__force void __iomem *)buf->vaddr); } + up_read(¤t->mm->mmap_sem); kfree(buf); }