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libvhost-user: Simplify VHOST_USER_REM_MEM_REG

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Let's avoid having to manually copy all elements. Copy only the ones
necessary to close the hole and perform the operation in-place without
a second array.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20220117041050.19718-4-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
David Hildenbrand 2022-01-17 04:12:32 +00:00 committed by Michael S. Tsirkin
parent 9f4e63491b
commit 4fd5ca829a
1 changed files with 14 additions and 16 deletions
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30
subprojects/libvhost-user/libvhost-user.c
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@ -811,10 +811,8 @@ static inline bool reg_equal(VuDevRegion *vudev_reg,
static bool
vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
int i, j;
bool found = false;
VuDevRegion shadow_regions[VHOST_USER_MAX_RAM_SLOTS] = {};
VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m;
int i;
if (vmsg->fd_num != 1) {
vmsg_close_fds(vmsg);
@ -841,28 +839,28 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
DPRINT(" mmap_offset 0x%016"PRIx64"\n",
msg_region->mmap_offset);
for (i = 0, j = 0; i < dev->nregions; i++) {
if (!reg_equal(&dev->regions[i], msg_region)) {
shadow_regions[j].gpa = dev->regions[i].gpa;
shadow_regions[j].size = dev->regions[i].size;
shadow_regions[j].qva = dev->regions[i].qva;
shadow_regions[j].mmap_addr = dev->regions[i].mmap_addr;
shadow_regions[j].mmap_offset = dev->regions[i].mmap_offset;
j++;
} else {
found = true;
for (i = 0; i < dev->nregions; i++) {
if (reg_equal(&dev->regions[i], msg_region)) {
VuDevRegion *r = &dev->regions[i];
void *m = (void *) (uintptr_t) r->mmap_addr;
if (m) {
munmap(m, r->size + r->mmap_offset);
}
break;
}
}
if (found) {
memcpy(dev->regions, shadow_regions,
sizeof(VuDevRegion) * VHOST_USER_MAX_RAM_SLOTS);
if (i < dev->nregions) {
/*
* Shift all affected entries by 1 to close the hole at index i and
* zero out the last entry.
*/
memmove(dev->regions + i, dev->regions + i + 1,
sizeof(VuDevRegion) * (dev->nregions - i - 1));
memset(dev->regions + dev->nregions - 1, 0,
sizeof(VuDevRegion));
DPRINT("Successfully removed a region\n");
dev->nregions--;
vmsg_set_reply_u64(vmsg, 0);