From f56f821feb7b36223f309e0ec05986bb137ce418 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Sun, 25 Mar 2012 19:47:41 +0200 Subject: mm: extend prefault helpers to fault in more than PAGE_SIZE drm/i915 wants to read/write more than one page in its fastpath and hence needs to prefault more than PAGE_SIZE bytes. Add new functions in filemap.h to make that possible. Also kill a copy&pasted spurious space in both functions while at it. v2: As suggested by Andrew Morton, add a multipage parameter to both functions to avoid the additional branch for the pagemap.c hotpath. My gcc 4.6 here seems to dtrt and indeed reap these branches where not needed. v3: Becaus I couldn't find a way around adding a uaddr += PAGE_SIZE to the filemap.c hotpaths (that the compiler couldn't remove again), let's go with separate new functions for the multipage use-case. v4: Adjust comment to CodingStlye and fix spelling. Acked-by: Andrew Morton Signed-off-by: Daniel Vetter --- include/linux/pagemap.h | 64 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 62 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index cfaaa6949b8b..c93a9a9bcd35 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -426,7 +426,7 @@ static inline int fault_in_pages_writeable(char __user *uaddr, int size) */ if (((unsigned long)uaddr & PAGE_MASK) != ((unsigned long)end & PAGE_MASK)) - ret = __put_user(0, end); + ret = __put_user(0, end); } return ret; } @@ -445,13 +445,73 @@ static inline int fault_in_pages_readable(const char __user *uaddr, int size) if (((unsigned long)uaddr & PAGE_MASK) != ((unsigned long)end & PAGE_MASK)) { - ret = __get_user(c, end); + ret = __get_user(c, end); (void)c; } } return ret; } +/* + * Multipage variants of the above prefault helpers, useful if more than + * PAGE_SIZE of data needs to be prefaulted. These are separate from the above + * functions (which only handle up to PAGE_SIZE) to avoid clobbering the + * filemap.c hotpaths. + */ +static inline int fault_in_multipages_writeable(char __user *uaddr, int size) +{ + int ret; + const char __user *end = uaddr + size - 1; + + if (unlikely(size == 0)) + return 0; + + /* + * Writing zeroes into userspace here is OK, because we know that if + * the zero gets there, we'll be overwriting it. + */ + while (uaddr <= end) { + ret = __put_user(0, uaddr); + if (ret != 0) + return ret; + uaddr += PAGE_SIZE; + } + + /* Check whether the range spilled into the next page. */ + if (((unsigned long)uaddr & PAGE_MASK) == + ((unsigned long)end & PAGE_MASK)) + ret = __put_user(0, end); + + return ret; +} + +static inline int fault_in_multipages_readable(const char __user *uaddr, + int size) +{ + volatile char c; + int ret; + const char __user *end = uaddr + size - 1; + + if (unlikely(size == 0)) + return 0; + + while (uaddr <= end) { + ret = __get_user(c, uaddr); + if (ret != 0) + return ret; + uaddr += PAGE_SIZE; + } + + /* Check whether the range spilled into the next page. */ + if (((unsigned long)uaddr & PAGE_MASK) == + ((unsigned long)end & PAGE_MASK)) { + ret = __get_user(c, end); + (void)c; + } + + return ret; +} + int add_to_page_cache_locked(struct page *page, struct address_space *mapping, pgoff_t index, gfp_t gfp_mask); int add_to_page_cache_lru(struct page *page, struct address_space *mapping, -- cgit v1.2.3 From 9923777dff4543050fdf938cf6b19f6d4376b7c5 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Sat, 14 Apr 2012 18:03:10 +0200 Subject: mm: fixup compilation error due to an asm write through a const pointer This regression has been introduced in commit f56f821feb7b36223f309e0ec05986bb137ce418 Author: Daniel Vetter Date: Sun Mar 25 19:47:41 2012 +0200 mm: extend prefault helpers to fault in more than PAGE_SIZE I have failed to notice this because x86 asm seems to happily compile things as-is. Reported-by: Geert Uytterhoeven Signed-off-by: Dave Airlie --- include/linux/pagemap.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index c93a9a9bcd35..efa26b4da8d2 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -461,7 +461,7 @@ static inline int fault_in_pages_readable(const char __user *uaddr, int size) static inline int fault_in_multipages_writeable(char __user *uaddr, int size) { int ret; - const char __user *end = uaddr + size - 1; + char __user *end = uaddr + size - 1; if (unlikely(size == 0)) return 0; -- cgit v1.2.3 From 1a39b310e920bb7098067d96411b31e459ae8f32 Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Mon, 16 Apr 2012 16:26:02 -0400 Subject: vgaarb: Add support for setting the default video device (v2) The default VGA device is a somewhat fluid concept on platforms with multiple GPUs. Add support for setting it so switching code can update things appropriately, and make sure that the sysfs code returns the right device if it's changed. v2: Updated to fix builds when __ARCH_HAS_VGA_DEFAULT_DEVICE is false. Signed-off-by: Matthew Garrett Acked-by: H. Peter Anvin Acked-by: benh@kernel.crashing.org Cc: airlied@redhat.com Signed-off-by: Dave Airlie --- include/linux/vgaarb.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index 9c3120dca294..759a25ba0539 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -31,6 +31,7 @@ #ifndef LINUX_VGA_H #define LINUX_VGA_H +#include