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lazy-pages: uffd_{copy, zeropage}: rework error handling

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Improve code readability and take into account that even if
uffdio_{copy,zeropage} has failed, some pages had been updated.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This commit is contained in:
Mike Rapoport 2018-06-06 17:30:58 +03:00 committed by Andrei Vagin
parent a72719d365
commit 48fcb8934c
1 changed files with 36 additions and 24 deletions
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60
criu/uffd.c
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@ -814,32 +814,44 @@ static int handle_exit(struct lazy_pages_info *lpi)
return 0;
}
static int uffd_check_op_error(struct lazy_pages_info *lpi, const char *op,
unsigned long len, unsigned long rc_len, int rc)
static bool uffd_recoverable_error(int mcopy_rc)
{
if (rc) {
if (errno == ENOSPC || errno == ESRCH) {
handle_exit(lpi);
return 0;
}
if (rc_len != -EEXIST) {
lp_perror(lpi, "%s: rc:%d copy:%ld, errno:%d",
op, rc, rc_len, errno);
return -1;
}
} else if (rc_len != len) {
lp_err(lpi, "%s unexpected size %ld\n", op, rc_len);
if (errno == EAGAIN || errno == ENOENT || errno == EEXIST)
return true;
if (mcopy_rc == -ENOENT || mcopy_rc == -EEXIST)
return true;
return false;
}
static int uffd_check_op_error(struct lazy_pages_info *lpi, const char *op,
int *nr_pages, long mcopy_rc)
{
if (errno == ENOSPC || errno == ESRCH) {
handle_exit(lpi);
return 0;
}
if (!uffd_recoverable_error(mcopy_rc)) {
lp_perror(lpi, "%s: mcopy_rc:%ld", op, mcopy_rc);
return -1;
}
lp_debug(lpi, "%s: mcopy_rc:%ld, errno:%d\n", op, mcopy_rc, errno);
if (mcopy_rc <= 0)
*nr_pages = 0;
else
*nr_pages = mcopy_rc / PAGE_SIZE;
return 0;
}
static int uffd_copy(struct lazy_pages_info *lpi, __u64 address, int nr_pages)
static int uffd_copy(struct lazy_pages_info *lpi, __u64 address, int *nr_pages)
{
struct uffdio_copy uffdio_copy;
unsigned long len = nr_pages * page_size();
int rc;
unsigned long len = *nr_pages * page_size();
uffdio_copy.dst = address;
uffdio_copy.src = (unsigned long)lpi->buf;
@ -848,11 +860,11 @@ static int uffd_copy(struct lazy_pages_info *lpi, __u64 address, int nr_pages)
uffdio_copy.copy = 0;
lp_debug(lpi, "uffd_copy: 0x%llx/%ld\n", uffdio_copy.dst, len);
rc = ioctl(lpi->lpfd.fd, UFFDIO_COPY, &uffdio_copy);
if (uffd_check_op_error(lpi, "copy", len, uffdio_copy.copy, rc))
if (ioctl(lpi->lpfd.fd, UFFDIO_COPY, &uffdio_copy) &&
uffd_check_op_error(lpi, "copy", nr_pages, uffdio_copy.copy))
return -1;
lpi->copied_pages += nr_pages;
lpi->copied_pages += *nr_pages;
return 0;
}
@ -895,7 +907,7 @@ static int uffd_io_complete(struct page_read *pr, unsigned long img_addr, int nr
req_pages = (req->end - req->start) / PAGE_SIZE;
nr = min(nr, req_pages);
ret = uffd_copy(lpi, addr, nr);
ret = uffd_copy(lpi, addr, &nr);
if (ret < 0)
return ret;
@ -916,15 +928,15 @@ static int uffd_zero(struct lazy_pages_info *lpi, __u64 address, int nr_pages)
{
struct uffdio_zeropage uffdio_zeropage;
unsigned long len = page_size() * nr_pages;
int rc;
uffdio_zeropage.range.start = address;
uffdio_zeropage.range.len = len;
uffdio_zeropage.mode = 0;
lp_debug(lpi, "zero page at 0x%llx\n", address);
rc = ioctl(lpi->lpfd.fd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
if (uffd_check_op_error(lpi, "zero", len, uffdio_zeropage.zeropage, rc))
if (ioctl(lpi->lpfd.fd, UFFDIO_ZEROPAGE, &uffdio_zeropage) &&
uffd_check_op_error(lpi, "zero", &nr_pages,
uffdio_zeropage.zeropage))
return -1;
return 0;