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Remove alignment requirements for KVA buffer mapping.

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After r368124 pbuf_zone has extra page to handle this particular case.
This commit is contained in:
Alexander Motin 2020-11-29 01:30:17 +00:00
parent 1770bae5f8
commit 83f6b50123
1 changed files with 5 additions and 23 deletions
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28
sys/kern/kern_physio.c
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@ -30,11 +30,14 @@ __FBSDID("$FreeBSD$");
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/racct.h>
#include <sys/rwlock.h>
#include <sys/uio.h>
#include <geom/geom.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
@ -107,7 +110,7 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
pbuf = uma_zalloc(pbuf_zone, M_WAITOK);
MPASS((pbuf->b_flags & B_MAXPHYS) != 0);
sa = pbuf->b_data;
maxpages = btoc(maxphys);
maxpages = PBUF_PAGES;
pages = pbuf->b_pages;
}
prot = VM_PROT_READ;
@ -147,28 +150,6 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
bp->bio_length = dev->si_iosize_max;
if (bp->bio_length > maxphys)
bp->bio_length = maxphys;
/*
* Make sure the pbuf can map the request.
* The pbuf has kvasize = maxphys, so a request
* larger than maxphys - PAGE_SIZE must be
* page aligned or it will be fragmented.
*/
poff = (vm_offset_t)base & PAGE_MASK;
if (pbuf && bp->bio_length + poff > pbuf->b_kvasize) {
if (dev->si_flags & SI_NOSPLIT) {
uprintf("%s: request ptr %p is not "
"on a page boundary; cannot split "
"request\n", devtoname(dev),
base);
error = EFBIG;
goto doerror;
}
bp->bio_length = pbuf->b_kvasize;
if (poff != 0)
bp->bio_length -= PAGE_SIZE;
}
bp->bio_bcount = bp->bio_length;
bp->bio_dev = dev;
@ -180,6 +161,7 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
error = EFAULT;
goto doerror;
}
poff = (vm_offset_t)base & PAGE_MASK;
if (pbuf && sa) {
pmap_qenter((vm_offset_t)sa,
pages, npages);