diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 186 |
1 files changed, 68 insertions, 118 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index a074fceb67d3..be832b6f8279 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -5,7 +5,7 @@ * * Added devfs support. * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> - * Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> + * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> */ #include <linux/mm.h> @@ -26,7 +26,6 @@ #include <linux/bootmem.h> #include <linux/splice.h> #include <linux/pfn.h> -#include <linux/smp_lock.h> #include <asm/uaccess.h> #include <asm/io.h> @@ -35,6 +34,16 @@ # include <linux/efi.h> #endif +static inline unsigned long size_inside_page(unsigned long start, + unsigned long size) +{ + unsigned long sz; + + sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); + + return min(sz, size); +} + /* * Architectures vary in how they handle caching for addresses * outside of main memory. @@ -44,7 +53,7 @@ static inline int uncached_access(struct file *file, unsigned long addr) { #if defined(CONFIG_IA64) /* - * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. + * On ia64, we ignore O_DSYNC because we cannot tolerate memory attribute aliases. */ return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); #elif defined(CONFIG_MIPS) @@ -57,9 +66,9 @@ static inline int uncached_access(struct file *file, unsigned long addr) #else /* * Accessing memory above the top the kernel knows about or through a file pointer - * that was marked O_SYNC will be done non-cached. + * that was marked O_DSYNC will be done non-cached. */ - if (file->f_flags & O_SYNC) + if (file->f_flags & O_DSYNC) return 1; return addr >= __pa(high_memory); #endif @@ -127,9 +136,7 @@ static ssize_t read_mem(struct file * file, char __user * buf, #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED /* we don't have page 0 mapped on sparc and m68k.. */ if (p < PAGE_SIZE) { - sz = PAGE_SIZE - p; - if (sz > count) - sz = count; + sz = size_inside_page(p, count); if (sz > 0) { if (clear_user(buf, sz)) return -EFAULT; @@ -142,15 +149,9 @@ static ssize_t read_mem(struct file * file, char __user * buf, #endif while (count > 0) { - /* - * Handle first page in case it's not aligned - */ - if (-p & (PAGE_SIZE - 1)) - sz = -p & (PAGE_SIZE - 1); - else - sz = PAGE_SIZE; + unsigned long remaining; - sz = min_t(unsigned long, sz, count); + sz = size_inside_page(p, count); if (!range_is_allowed(p >> PAGE_SHIFT, count)) return -EPERM; @@ -164,12 +165,10 @@ static ssize_t read_mem(struct file * file, char __user * buf, if (!ptr) return -EFAULT; - if (copy_to_user(buf, ptr, sz)) { - unxlate_dev_mem_ptr(p, ptr); - return -EFAULT; - } - + remaining = copy_to_user(buf, ptr, sz); unxlate_dev_mem_ptr(p, ptr); + if (remaining) + return -EFAULT; buf += sz; p += sz; @@ -197,9 +196,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf, #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED /* we don't have page 0 mapped on sparc and m68k.. */ if (p < PAGE_SIZE) { - unsigned long sz = PAGE_SIZE - p; - if (sz > count) - sz = count; + sz = size_inside_page(p, count); /* Hmm. Do something? */ buf += sz; p += sz; @@ -209,15 +206,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf, #endif while (count > 0) { - /* - * Handle first page in case it's not aligned - */ - if (-p & (PAGE_SIZE - 1)) - sz = -p & (PAGE_SIZE - 1); - else - sz = PAGE_SIZE; - - sz = min_t(unsigned long, sz, count); + sz = size_inside_page(p, count); if (!range_is_allowed(p >> PAGE_SHIFT, sz)) return -EPERM; @@ -235,16 +224,14 @@ static ssize_t write_mem(struct file * file, const char __user * buf, } copied = copy_from_user(ptr, buf, sz); + unxlate_dev_mem_ptr(p, ptr); if (copied) { written += sz - copied; - unxlate_dev_mem_ptr(p, ptr); if (written) break; return -EFAULT; } - unxlate_dev_mem_ptr(p, ptr); - buf += sz; p += sz; count -= sz; @@ -418,27 +405,18 @@ static ssize_t read_kmem(struct file *file, char __user *buf, #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED /* we don't have page 0 mapped on sparc and m68k.. */ if (p < PAGE_SIZE && low_count > 0) { - size_t tmp = PAGE_SIZE - p; - if (tmp > low_count) tmp = low_count; - if (clear_user(buf, tmp)) + sz = size_inside_page(p, low_count); + if (clear_user(buf, sz)) return -EFAULT; - buf += tmp; - p += tmp; - read += tmp; - low_count -= tmp; - count -= tmp; + buf += sz; + p += sz; + read += sz; + low_count -= sz; + count -= sz; } #endif while (low_count > 0) { - /* - * Handle first page in case it's not aligned - */ - if (-p & (PAGE_SIZE - 1)) - sz = -p & (PAGE_SIZE - 1); - else - sz = PAGE_SIZE; - - sz = min_t(unsigned long, sz, low_count); + sz = size_inside_page(p, low_count); /* * On ia64 if a page has been mapped somewhere as @@ -462,21 +440,18 @@ static ssize_t read_kmem(struct file *file, char __user *buf, if (!kbuf) return -ENOMEM; while (count > 0) { - int len = count; - - if (len > PAGE_SIZE) - len = PAGE_SIZE; - len = vread(kbuf, (char *)p, len); - if (!len) + sz = size_inside_page(p, count); + sz = vread(kbuf, (char *)p, sz); + if (!sz) break; - if (copy_to_user(buf, kbuf, len)) { + if (copy_to_user(buf, kbuf, sz)) { free_page((unsigned long)kbuf); return -EFAULT; } - count -= len; - buf += len; - read += len; - p += len; + count -= sz; + buf += sz; + read += sz; + p += sz; } free_page((unsigned long)kbuf); } @@ -486,7 +461,7 @@ static ssize_t read_kmem(struct file *file, char __user *buf, static inline ssize_t -do_write_kmem(void *p, unsigned long realp, const char __user * buf, +do_write_kmem(unsigned long p, const char __user *buf, size_t count, loff_t *ppos) { ssize_t written, sz; @@ -495,14 +470,11 @@ do_write_kmem(void *p, unsigned long realp, const char __user * buf, written = 0; #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED /* we don't have page 0 mapped on sparc and m68k.. */ - if (realp < PAGE_SIZE) { - unsigned long sz = PAGE_SIZE - realp; - if (sz > count) - sz = count; + if (p < PAGE_SIZE) { + sz = size_inside_page(p, count); /* Hmm. Do something? */ buf += sz; p += sz; - realp += sz; count -= sz; written += sz; } @@ -510,22 +482,15 @@ do_write_kmem(void *p, unsigned long realp, const char __user * buf, while (count > 0) { char *ptr; - /* - * Handle first page in case it's not aligned - */ - if (-realp & (PAGE_SIZE - 1)) - sz = -realp & (PAGE_SIZE - 1); - else - sz = PAGE_SIZE; - sz = min_t(unsigned long, sz, count); + sz = size_inside_page(p, count); /* * On ia64 if a page has been mapped somewhere as * uncached, then it must also be accessed uncached * by the kernel or data corruption may occur */ - ptr = xlate_dev_kmem_ptr(p); + ptr = xlate_dev_kmem_ptr((char *)p); copied = copy_from_user(ptr, buf, sz); if (copied) { @@ -536,7 +501,6 @@ do_write_kmem(void *p, unsigned long realp, const char __user * buf, } buf += sz; p += sz; - realp += sz; count -= sz; written += sz; } @@ -555,19 +519,14 @@ static ssize_t write_kmem(struct file * file, const char __user * buf, unsigned long p = *ppos; ssize_t wrote = 0; ssize_t virtr = 0; - ssize_t written; char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ if (p < (unsigned long) high_memory) { - - wrote = count; - if (count > (unsigned long) high_memory - p) - wrote = (unsigned long) high_memory - p; - - written = do_write_kmem((void*)p, p, buf, wrote, ppos); - if (written != wrote) - return written; - wrote = written; + unsigned long to_write = min_t(unsigned long, count, + (unsigned long)high_memory - p); + wrote = do_write_kmem(p, buf, to_write, ppos); + if (wrote != to_write) + return wrote; p += wrote; buf += wrote; count -= wrote; @@ -578,24 +537,21 @@ static ssize_t write_kmem(struct file * file, const char __user * buf, if (!kbuf) return wrote ? wrote : -ENOMEM; while (count > 0) { - int len = count; - - if (len > PAGE_SIZE) - len = PAGE_SIZE; - if (len) { - written = copy_from_user(kbuf, buf, len); - if (written) { - if (wrote + virtr) - break; - free_page((unsigned long)kbuf); - return -EFAULT; - } + unsigned long sz = size_inside_page(p, count); + unsigned long n; + + n = copy_from_user(kbuf, buf, sz); + if (n) { + if (wrote + virtr) + break; + free_page((unsigned long)kbuf); + return -EFAULT; } - len = vwrite(kbuf, (char *)p, len); - count -= len; - buf += len; - virtr += len; - p += len; + sz = vwrite(kbuf, (char *)p, sz); + count -= sz; + buf += sz; + virtr += sz; + p += sz; } free_page((unsigned long)kbuf); } @@ -892,29 +848,23 @@ static int memory_open(struct inode *inode, struct file *filp) { int minor; const struct memdev *dev; - int ret = -ENXIO; - - lock_kernel(); minor = iminor(inode); if (minor >= ARRAY_SIZE(devlist)) - goto out; + return -ENXIO; dev = &devlist[minor]; if (!dev->fops) - goto out; + return -ENXIO; filp->f_op = dev->fops; if (dev->dev_info) filp->f_mapping->backing_dev_info = dev->dev_info; if (dev->fops->open) - ret = dev->fops->open(inode, filp); - else - ret = 0; -out: - unlock_kernel(); - return ret; + return dev->fops->open(inode, filp); + + return 0; } static const struct file_operations memory_fops = { |