diff options
Diffstat (limited to 'sys/kern/subr_sglist.c')
| -rw-r--r-- | sys/kern/subr_sglist.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/sys/kern/subr_sglist.c b/sys/kern/subr_sglist.c index ea77161..c66973a 100644 --- a/sys/kern/subr_sglist.c +++ b/sys/kern/subr_sglist.c @@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/kernel.h> +#include <sys/bio.h> #include <sys/malloc.h> #include <sys/mbuf.h> #include <sys/proc.h> @@ -40,6 +41,7 @@ __FBSDID("$FreeBSD$"); #include <sys/uio.h> #include <vm/vm.h> +#include <vm/vm_page.h> #include <vm/pmap.h> #include <vm/vm_map.h> @@ -239,6 +241,44 @@ sglist_append(struct sglist *sg, void *buf, size_t len) } /* + * Append the segments to describe a bio's data to a scatter/gather list. + * If there are insufficient segments, then this fails with EFBIG. + * + * NOTE: This function expects bio_bcount to be initialized. + */ +int +sglist_append_bio(struct sglist *sg, struct bio *bp) +{ + struct sgsave save; + vm_paddr_t paddr; + size_t len, tlen; + int error, i, ma_offs; + + if ((bp->bio_flags & BIO_UNMAPPED) == 0) { + error = sglist_append(sg, bp->bio_data, bp->bio_bcount); + return (error); + } + + if (sg->sg_maxseg == 0) + return (EINVAL); + + SGLIST_SAVE(sg, save); + tlen = bp->bio_bcount; + ma_offs = bp->bio_ma_offset; + for (i = 0; tlen > 0; i++, tlen -= len) { + len = min(PAGE_SIZE - ma_offs, tlen); + paddr = VM_PAGE_TO_PHYS(bp->bio_ma[i]) + ma_offs; + error = sglist_append_phys(sg, paddr, len); + if (error) { + SGLIST_RESTORE(sg, save); + return (error); + } + ma_offs = 0; + } + return (0); +} + +/* * Append a single physical address range to a scatter/gather list. * If there are insufficient segments, then this fails with EFBIG. */ |
