diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/mem.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index d633974e7f8b..a33163dbb913 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -22,6 +22,7 @@ #include <linux/device.h> #include <linux/highmem.h> #include <linux/backing-dev.h> +#include <linux/shmem_fs.h> #include <linux/splice.h> #include <linux/pfn.h> #include <linux/export.h> @@ -657,6 +658,28 @@ static int mmap_zero(struct file *file, struct vm_area_struct *vma) return 0; } +static unsigned long get_unmapped_area_zero(struct file *file, + unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags) +{ +#ifdef CONFIG_MMU + if (flags & MAP_SHARED) { + /* + * mmap_zero() will call shmem_zero_setup() to create a file, + * so use shmem's get_unmapped_area in case it can be huge; + * and pass NULL for file as in mmap.c's get_unmapped_area(), + * so as not to confuse shmem with our handle on "/dev/zero". + */ + return shmem_get_unmapped_area(NULL, addr, len, pgoff, flags); + } + + /* Otherwise flags & MAP_PRIVATE: with no shmem object beneath it */ + return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); +#else + return -ENOSYS; +#endif +} + static ssize_t write_full(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { @@ -764,6 +787,7 @@ static const struct file_operations zero_fops = { .read_iter = read_iter_zero, .write_iter = write_iter_zero, .mmap = mmap_zero, + .get_unmapped_area = get_unmapped_area_zero, #ifndef CONFIG_MMU .mmap_capabilities = zero_mmap_capabilities, #endif |