diff options
Diffstat (limited to 'include/linux/bio.h')
| -rw-r--r-- | include/linux/bio.h | 50 |
1 files changed, 47 insertions, 3 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h index b244108a27a8..ffc38fca9c1e 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -21,6 +21,8 @@ #define __LINUX_BIO_H #include <linux/kdev_t.h> +#include <linux/highmem.h> + /* Platforms may set this to teach the BIO layer about IOMMU hardware. */ #include <asm/io.h> #ifndef BIO_VMERGE_BOUNDARY @@ -47,9 +49,6 @@ struct bio_vec { unsigned int bv_offset; }; -/* - * weee, c forward decl... - */ struct bio; typedef void (bio_end_io_t) (struct bio *); typedef void (bio_destructor_t) (struct bio *); @@ -206,4 +205,49 @@ extern inline void bio_init(struct bio *); extern int bio_ioctl(kdev_t, unsigned int, unsigned long); +#ifdef CONFIG_HIGHMEM +/* + * remember to add offset! and never ever reenable interrupts between a + * bio_kmap_irq and bio_kunmap_irq!! + * + * This function MUST be inlined - it plays with the CPU interrupt flags. + * Hence the `extern inline'. + */ +extern inline char *bio_kmap_irq(struct bio *bio, unsigned long *flags) +{ + unsigned long addr; + + __save_flags(*flags); + + /* + * could be low + */ + if (!PageHighMem(bio_page(bio))) + return bio_data(bio); + + /* + * it's a highmem page + */ + __cli(); + addr = (unsigned long) kmap_atomic(bio_page(bio), KM_BIO_SRC_IRQ); + + if (addr & ~PAGE_MASK) + BUG(); + + return (char *) addr + bio_offset(bio); +} + +extern inline void bio_kunmap_irq(char *buffer, unsigned long *flags) +{ + unsigned long ptr = (unsigned long) buffer & PAGE_MASK; + + kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ); + __restore_flags(*flags); +} + +#else +#define bio_kmap_irq(bio, flags) (bio_data(bio)) +#define bio_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0) +#endif + #endif /* __LINUX_BIO_H */ |