| Message ID | 20201214163623.2127-20-bouyer@netbsd.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | NetBSD fixes | expand |
On Mon, Dec 14, 2020 at 05:36:18PM +0100, Manuel Bouyer wrote: > --- > tools/xenpaging/xenpaging.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/tools/xenpaging/xenpaging.c b/tools/xenpaging/xenpaging.c > index 33098046c2..39c8c83b4b 100644 > --- a/tools/xenpaging/xenpaging.c > +++ b/tools/xenpaging/xenpaging.c > @@ -180,10 +180,11 @@ static int xenpaging_get_tot_pages(struct xenpaging *paging) > static void *init_page(void) > { > void *buffer; > + int rc; > > /* Allocated page memory */ > - errno = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); > - if ( errno != 0 ) > + rc = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); > + if ( rc != 0 ) I think the point of setting errno here is because posix_memalign doesn't set it and instead returns an error code. The caller of init_page uses PERROR in order to print the error which his expected to be in errno. I don't think this is the only place in Xen code that errno is set, why are the others fine but not this instance? Thanks, Roger.
On Tue, Dec 29, 2020 at 03:38:53PM +0100, Roger Pau Monné wrote: > On Mon, Dec 14, 2020 at 05:36:18PM +0100, Manuel Bouyer wrote: > > --- > > tools/xenpaging/xenpaging.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/tools/xenpaging/xenpaging.c b/tools/xenpaging/xenpaging.c > > index 33098046c2..39c8c83b4b 100644 > > --- a/tools/xenpaging/xenpaging.c > > +++ b/tools/xenpaging/xenpaging.c > > @@ -180,10 +180,11 @@ static int xenpaging_get_tot_pages(struct xenpaging *paging) > > static void *init_page(void) > > { > > void *buffer; > > + int rc; > > > > /* Allocated page memory */ > > - errno = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); > > - if ( errno != 0 ) > > + rc = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); > > + if ( rc != 0 ) > > I think the point of setting errno here is because posix_memalign > doesn't set it and instead returns an error code. The caller of > init_page uses PERROR in order to print the error which his expected to > be in errno. I understand this. But on NetBSD, errno is: #define errno (*__errno()) (I think this is related to thread-safety). > > I don't think this is the only place in Xen code that errno is set, why > are the others fine but not this instance? probably this code is not used on NetBSD ?
On Mon, Jan 04, 2021 at 11:56:14AM +0100, Manuel Bouyer wrote: > On Tue, Dec 29, 2020 at 03:38:53PM +0100, Roger Pau Monné wrote: > > On Mon, Dec 14, 2020 at 05:36:18PM +0100, Manuel Bouyer wrote: > > > --- > > > tools/xenpaging/xenpaging.c | 5 +++-- > > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > > > diff --git a/tools/xenpaging/xenpaging.c b/tools/xenpaging/xenpaging.c > > > index 33098046c2..39c8c83b4b 100644 > > > --- a/tools/xenpaging/xenpaging.c > > > +++ b/tools/xenpaging/xenpaging.c > > > @@ -180,10 +180,11 @@ static int xenpaging_get_tot_pages(struct xenpaging *paging) > > > static void *init_page(void) > > > { > > > void *buffer; > > > + int rc; > > > > > > /* Allocated page memory */ > > > - errno = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); > > > - if ( errno != 0 ) > > > + rc = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); > > > + if ( rc != 0 ) > > > > I think the point of setting errno here is because posix_memalign > > doesn't set it and instead returns an error code. The caller of > > init_page uses PERROR in order to print the error which his expected to > > be in errno. > > I understand this. But on NetBSD, errno is: > #define errno (*__errno()) > > (I think this is related to thread-safety). > > > > > I don't think this is the only place in Xen code that errno is set, why > > are the others fine but not this instance? > > probably this code is not used on NetBSD ? I was wrong, errno is writable but it needs #include <errno.h> I reverted this a fixed it the right way
diff --git a/tools/xenpaging/xenpaging.c b/tools/xenpaging/xenpaging.c index 33098046c2..39c8c83b4b 100644 --- a/tools/xenpaging/xenpaging.c +++ b/tools/xenpaging/xenpaging.c @@ -180,10 +180,11 @@ static int xenpaging_get_tot_pages(struct xenpaging *paging) static void *init_page(void) { void *buffer; + int rc; /* Allocated page memory */ - errno = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); - if ( errno != 0 ) + rc = posix_memalign(&buffer, XC_PAGE_SIZE, XC_PAGE_SIZE); + if ( rc != 0 ) return NULL; /* Lock buffer in memory so it can't be paged out */