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Tidy up the unmapped I/O code in qphysio.

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- Move some blocks around to reduce the number of 'if (unmap)' checks.
- Use 'pbuf == NULL' instead of 'unmap'.
- Use nitems.
- Pull an assignment out of an if expression.

Reviewed by:	kib
Sponsored by:	Chelsio Communications
This commit is contained in:
John Baldwin 2016-03-31 17:27:30 +00:00
parent fb71c286e8
commit 4d805eacfa
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=297464
1 changed files with 17 additions and 23 deletions
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40
sys/kern/vfs_aio.c
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@ -1173,7 +1173,7 @@ aio_qphysio(struct proc *p, struct kaiocb *job)
struct cdevsw *csw;
struct cdev *dev;
struct kaioinfo *ki;
int error, ref, unmap, poff;
int error, ref, poff;
vm_prot_t prot;
cb = &job->uaiocb;
@ -1206,12 +1206,13 @@ aio_qphysio(struct proc *p, struct kaiocb *job)
ki = p->p_aioinfo;
poff = (vm_offset_t)cb->aio_buf & PAGE_MASK;
unmap = ((dev->si_flags & SI_UNMAPPED) && unmapped_buf_allowed);
if (unmap) {
if ((dev->si_flags & SI_UNMAPPED) && unmapped_buf_allowed) {
if (cb->aio_nbytes > MAXPHYS) {
error = -1;
goto unref;
}
pbuf = NULL;
} else {
if (cb->aio_nbytes > MAXPHYS - poff) {
error = -1;
@ -1221,18 +1222,14 @@ aio_qphysio(struct proc *p, struct kaiocb *job)
error = -1;
goto unref;
}
}
job->bp = bp = g_alloc_bio();
if (!unmap) {
job->pbuf = pbuf = (struct buf *)getpbuf(NULL);
BUF_KERNPROC(pbuf);
} else
pbuf = NULL;
AIO_LOCK(ki);
if (!unmap)
AIO_LOCK(ki);
ki->kaio_buffer_count++;
AIO_UNLOCK(ki);
AIO_UNLOCK(ki);
}
job->bp = bp = g_alloc_bio();
bp->bio_length = cb->aio_nbytes;
bp->bio_bcount = cb->aio_nbytes;
@ -1246,17 +1243,18 @@ aio_qphysio(struct proc *p, struct kaiocb *job)
prot = VM_PROT_READ;
if (cb->aio_lio_opcode == LIO_READ)
prot |= VM_PROT_WRITE; /* Less backwards than it looks */
if ((job->npages = vm_fault_quick_hold_pages(
&curproc->p_vmspace->vm_map,
job->npages = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map,
(vm_offset_t)bp->bio_data, bp->bio_length, prot, job->pages,
sizeof(job->pages)/sizeof(job->pages[0]))) < 0) {
nitems(job->pages));
if (job->npages < 0) {
error = EFAULT;
goto doerror;
}
if (!unmap) {
if (pbuf != NULL) {
pmap_qenter((vm_offset_t)pbuf->b_data,
job->pages, job->npages);
bp->bio_data = pbuf->b_data + poff;
atomic_add_int(&num_buf_aio, 1);
} else {
bp->bio_ma = job->pages;
bp->bio_ma_n = job->npages;
@ -1265,20 +1263,16 @@ aio_qphysio(struct proc *p, struct kaiocb *job)
bp->bio_flags |= BIO_UNMAPPED;
}
if (!unmap)
atomic_add_int(&num_buf_aio, 1);
/* Perform transfer. */
csw->d_strategy(bp);
dev_relthread(dev, ref);
return (0);
doerror:
AIO_LOCK(ki);
if (!unmap)
if (pbuf != NULL) {
AIO_LOCK(ki);
ki->kaio_buffer_count--;
AIO_UNLOCK(ki);
if (pbuf) {
AIO_UNLOCK(ki);
relpbuf(pbuf, NULL);
job->pbuf = NULL;
}