* [PATCH v2 0/2] tools/xenstore: simplify xenstored main loop
@ 2021-05-14 11:56 Juergen Gross
2021-05-14 11:56 ` [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct Juergen Gross
2021-05-14 11:56 ` [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop Juergen Gross
0 siblings, 2 replies; 8+ messages in thread
From: Juergen Gross @ 2021-05-14 11:56 UTC (permalink / raw)
To: xen-devel; +Cc: Juergen Gross, Ian Jackson, Wei Liu
Small series to make the main loop of xenstored more readable.
Changes in V2:
- split into two patches
- use const
- NO_SOCKETS handling
Juergen Gross (2):
tools/xenstore: move per connection read and write func hooks into a
struct
tools/xenstore: simplify xenstored main loop
tools/xenstore/xenstored_core.c | 121 ++++++++++++++----------------
tools/xenstore/xenstored_core.h | 21 +++---
tools/xenstore/xenstored_domain.c | 15 +++-
3 files changed, 79 insertions(+), 78 deletions(-)
--
2.26.2
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct
2021-05-14 11:56 [PATCH v2 0/2] tools/xenstore: simplify xenstored main loop Juergen Gross
@ 2021-05-14 11:56 ` Juergen Gross
2021-05-14 16:33 ` Julien Grall
2021-05-14 11:56 ` [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop Juergen Gross
1 sibling, 1 reply; 8+ messages in thread
From: Juergen Gross @ 2021-05-14 11:56 UTC (permalink / raw)
To: xen-devel; +Cc: Juergen Gross, Ian Jackson, Wei Liu
Put the interface type specific functions into an own structure and let
struct connection contain only a pointer to that new function vector.
Don't even define the socket based functions in case of NO_SOCKETS
(Mini-OS).
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- split off from V1 patch (Julien Grall)
- use const qualifier (Julien Grall)
- drop socket specific case for Mini-OS (Julien Grall)
---
tools/xenstore/xenstored_core.c | 44 +++++++++++++------------------
tools/xenstore/xenstored_core.h | 19 +++++++------
tools/xenstore/xenstored_domain.c | 13 +++++++--
3 files changed, 38 insertions(+), 38 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 4b7b71cfb3..856f518075 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -226,8 +226,8 @@ static bool write_messages(struct connection *conn)
sockmsg_string(out->hdr.msg.type),
out->hdr.msg.len,
out->buffer, conn);
- ret = conn->write(conn, out->hdr.raw + out->used,
- sizeof(out->hdr) - out->used);
+ ret = conn->funcs->write(conn, out->hdr.raw + out->used,
+ sizeof(out->hdr) - out->used);
if (ret < 0)
return false;
@@ -243,8 +243,8 @@ static bool write_messages(struct connection *conn)
return true;
}
- ret = conn->write(conn, out->buffer + out->used,
- out->hdr.msg.len - out->used);
+ ret = conn->funcs->write(conn, out->buffer + out->used,
+ out->hdr.msg.len - out->used);
if (ret < 0)
return false;
@@ -1531,8 +1531,8 @@ static void handle_input(struct connection *conn)
/* Not finished header yet? */
if (in->inhdr) {
if (in->used != sizeof(in->hdr)) {
- bytes = conn->read(conn, in->hdr.raw + in->used,
- sizeof(in->hdr) - in->used);
+ bytes = conn->funcs->read(conn, in->hdr.raw + in->used,
+ sizeof(in->hdr) - in->used);
if (bytes < 0)
goto bad_client;
in->used += bytes;
@@ -1557,8 +1557,8 @@ static void handle_input(struct connection *conn)
in->inhdr = false;
}
- bytes = conn->read(conn, in->buffer + in->used,
- in->hdr.msg.len - in->used);
+ bytes = conn->funcs->read(conn, in->buffer + in->used,
+ in->hdr.msg.len - in->used);
if (bytes < 0)
goto bad_client;
@@ -1581,7 +1581,7 @@ static void handle_output(struct connection *conn)
ignore_connection(conn);
}
-struct connection *new_connection(connwritefn_t *write, connreadfn_t *read)
+struct connection *new_connection(const struct interface_funcs *funcs)
{
struct connection *new;
@@ -1591,8 +1591,7 @@ struct connection *new_connection(connwritefn_t *write, connreadfn_t *read)
new->fd = -1;
new->pollfd_idx = -1;
- new->write = write;
- new->read = read;
+ new->funcs = funcs;
new->is_ignored = false;
new->transaction_started = 0;
INIT_LIST_HEAD(&new->out_list);
@@ -1621,20 +1620,8 @@ struct connection *get_connection_by_id(unsigned int conn_id)
static void accept_connection(int sock)
{
}
-
-int writefd(struct connection *conn, const void *data, unsigned int len)
-{
- errno = EBADF;
- return -1;
-}
-
-int readfd(struct connection *conn, void *data, unsigned int len)
-{
- errno = EBADF;
- return -1;
-}
#else
-int writefd(struct connection *conn, const void *data, unsigned int len)
+static int writefd(struct connection *conn, const void *data, unsigned int len)
{
int rc;
@@ -1650,7 +1637,7 @@ int writefd(struct connection *conn, const void *data, unsigned int len)
return rc;
}
-int readfd(struct connection *conn, void *data, unsigned int len)
+static int readfd(struct connection *conn, void *data, unsigned int len)
{
int rc;
@@ -1672,6 +1659,11 @@ int readfd(struct connection *conn, void *data, unsigned int len)
return rc;
}
+const struct interface_funcs socket_funcs = {
+ .write = writefd,
+ .read = readfd,
+};
+
static void accept_connection(int sock)
{
int fd;
@@ -1681,7 +1673,7 @@ static void accept_connection(int sock)
if (fd < 0)
return;
- conn = new_connection(writefd, readfd);
+ conn = new_connection(&socket_funcs);
if (conn)
conn->fd = fd;
else
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 6a6d0448e8..021e41076d 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -86,8 +86,11 @@ struct delayed_request {
};
struct connection;
-typedef int connwritefn_t(struct connection *, const void *, unsigned int);
-typedef int connreadfn_t(struct connection *, void *, unsigned int);
+
+struct interface_funcs {
+ int (*write)(struct connection *, const void *, unsigned int);
+ int (*read)(struct connection *, void *, unsigned int);
+};
struct connection
{
@@ -131,9 +134,8 @@ struct connection
/* My watches. */
struct list_head watches;
- /* Methods for communicating over this connection: write can be NULL */
- connwritefn_t *write;
- connreadfn_t *read;
+ /* Methods for communicating over this connection. */
+ const struct interface_funcs *funcs;
/* Support for live update: connection id. */
unsigned int conn_id;
@@ -196,7 +198,7 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node,
struct node *read_node(struct connection *conn, const void *ctx,
const char *name);
-struct connection *new_connection(connwritefn_t *write, connreadfn_t *read);
+struct connection *new_connection(const struct interface_funcs *funcs);
struct connection *get_connection_by_id(unsigned int conn_id);
void check_store(void);
void corrupt(struct connection *conn, const char *fmt, ...);
@@ -254,10 +256,7 @@ void finish_daemonize(void);
/* Open a pipe for signal handling */
void init_pipe(int reopen_log_pipe[2]);
-int writefd(struct connection *conn, const void *data, unsigned int len);
-int readfd(struct connection *conn, void *data, unsigned int len);
-
-extern struct interface_funcs socket_funcs;
+extern const struct interface_funcs socket_funcs;
extern xengnttab_handle **xgt_handle;
int remember_string(struct hashtable *hash, const char *str);
diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index 0c17937c0f..f3cd56050e 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -172,6 +172,11 @@ static int readchn(struct connection *conn, void *data, unsigned int len)
return len;
}
+static const struct interface_funcs domain_funcs = {
+ .write = writechn,
+ .read = readchn,
+};
+
static void *map_interface(domid_t domid)
{
return xengnttab_map_grant_ref(*xgt_handle, domid,
@@ -389,7 +394,7 @@ static int new_domain(struct domain *domain, int port, bool restore)
domain->introduced = true;
- domain->conn = new_connection(writechn, readchn);
+ domain->conn = new_connection(&domain_funcs);
if (!domain->conn) {
errno = ENOMEM;
return errno;
@@ -1288,10 +1293,14 @@ void read_state_connection(const void *ctx, const void *state)
struct domain *domain, *tdomain;
if (sc->conn_type == XS_STATE_CONN_TYPE_SOCKET) {
- conn = new_connection(writefd, readfd);
+#ifdef NO_SOCKETS
+ barf("socket based connection without sockets");
+#else
+ conn = new_connection(&socket_funcs);
if (!conn)
barf("error restoring connection");
conn->fd = sc->spec.socket_fd;
+#endif
} else {
domain = introduce_domain(ctx, sc->spec.ring.domid,
sc->spec.ring.evtchn, true);
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop
2021-05-14 11:56 [PATCH v2 0/2] tools/xenstore: simplify xenstored main loop Juergen Gross
2021-05-14 11:56 ` [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct Juergen Gross
@ 2021-05-14 11:56 ` Juergen Gross
2021-05-14 17:05 ` Julien Grall
1 sibling, 1 reply; 8+ messages in thread
From: Juergen Gross @ 2021-05-14 11:56 UTC (permalink / raw)
To: xen-devel; +Cc: Juergen Gross, Ian Jackson, Wei Liu
The main loop of xenstored is rather complicated due to different
handling of socket and ring-page interfaces. Unify that handling by
introducing interface type specific functions can_read() and
can_write().
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- split off function vector introduction (Julien Grall)
---
tools/xenstore/xenstored_core.c | 77 +++++++++++++++----------------
tools/xenstore/xenstored_core.h | 2 +
tools/xenstore/xenstored_domain.c | 2 +
3 files changed, 41 insertions(+), 40 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 856f518075..883a1a582a 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1659,9 +1659,34 @@ static int readfd(struct connection *conn, void *data, unsigned int len)
return rc;
}
+static bool socket_can_process(struct connection *conn, int mask)
+{
+ if (conn->pollfd_idx == -1)
+ return false;
+
+ if (fds[conn->pollfd_idx].revents & ~(POLLIN | POLLOUT)) {
+ talloc_free(conn);
+ return false;
+ }
+
+ return (fds[conn->pollfd_idx].revents & mask) && !conn->is_ignored;
+}
+
+static bool socket_can_write(struct connection *conn)
+{
+ return socket_can_process(conn, POLLOUT);
+}
+
+static bool socket_can_read(struct connection *conn)
+{
+ return socket_can_process(conn, POLLIN);
+}
+
const struct interface_funcs socket_funcs = {
.write = writefd,
.read = readfd,
+ .can_write = socket_can_write,
+ .can_read = socket_can_read,
};
static void accept_connection(int sock)
@@ -2296,47 +2321,19 @@ int main(int argc, char *argv[])
if (&next->list != &connections)
talloc_increase_ref_count(next);
- if (conn->domain) {
- if (domain_can_read(conn))
- handle_input(conn);
- if (talloc_free(conn) == 0)
- continue;
-
- talloc_increase_ref_count(conn);
- if (domain_can_write(conn) &&
- !list_empty(&conn->out_list))
- handle_output(conn);
- if (talloc_free(conn) == 0)
- continue;
- } else {
- if (conn->pollfd_idx != -1) {
- if (fds[conn->pollfd_idx].revents
- & ~(POLLIN|POLLOUT))
- talloc_free(conn);
- else if ((fds[conn->pollfd_idx].revents
- & POLLIN) &&
- !conn->is_ignored)
- handle_input(conn);
- }
- if (talloc_free(conn) == 0)
- continue;
-
- talloc_increase_ref_count(conn);
-
- if (conn->pollfd_idx != -1) {
- if (fds[conn->pollfd_idx].revents
- & ~(POLLIN|POLLOUT))
- talloc_free(conn);
- else if ((fds[conn->pollfd_idx].revents
- & POLLOUT) &&
- !conn->is_ignored)
- handle_output(conn);
- }
- if (talloc_free(conn) == 0)
- continue;
+ if (conn->funcs->can_read(conn))
+ handle_input(conn);
+ if (talloc_free(conn) == 0)
+ continue;
- conn->pollfd_idx = -1;
- }
+ talloc_increase_ref_count(conn);
+
+ if (conn->funcs->can_write(conn))
+ handle_output(conn);
+ if (talloc_free(conn) == 0)
+ continue;
+
+ conn->pollfd_idx = -1;
}
if (delayed_requests) {
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 021e41076d..c6e04c0708 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -90,6 +90,8 @@ struct connection;
struct interface_funcs {
int (*write)(struct connection *, const void *, unsigned int);
int (*read)(struct connection *, void *, unsigned int);
+ bool (*can_write)(struct connection *);
+ bool (*can_read)(struct connection *);
};
struct connection
diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index f3cd56050e..708bf68af0 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -175,6 +175,8 @@ static int readchn(struct connection *conn, void *data, unsigned int len)
static const struct interface_funcs domain_funcs = {
.write = writechn,
.read = readchn,
+ .can_write = domain_can_write,
+ .can_read = domain_can_read,
};
static void *map_interface(domid_t domid)
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct
2021-05-14 11:56 ` [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct Juergen Gross
@ 2021-05-14 16:33 ` Julien Grall
2021-05-17 6:07 ` Juergen Gross
0 siblings, 1 reply; 8+ messages in thread
From: Julien Grall @ 2021-05-14 16:33 UTC (permalink / raw)
To: Juergen Gross, xen-devel; +Cc: Ian Jackson, Wei Liu
Hi Juergen,
On 14/05/2021 12:56, Juergen Gross wrote:
> -struct connection *new_connection(connwritefn_t *write, connreadfn_t *read);
> +struct connection *new_connection(const struct interface_funcs *funcs);
> struct connection *get_connection_by_id(unsigned int conn_id);
> void check_store(void);
> void corrupt(struct connection *conn, const char *fmt, ...);
> @@ -254,10 +256,7 @@ void finish_daemonize(void);
> /* Open a pipe for signal handling */
> void init_pipe(int reopen_log_pipe[2]);
>
> -int writefd(struct connection *conn, const void *data, unsigned int len);
> -int readfd(struct connection *conn, void *data, unsigned int len);
> -
> -extern struct interface_funcs socket_funcs;
> +extern const struct interface_funcs socket_funcs;
Shouldn't this be protected with #ifdef NO_SOCKETS?
The rest looks good to me:
Reviewed-by: Julien Grall <jgrall@amazon.com>
Cheers,
--
Julien Grall
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop
2021-05-14 11:56 ` [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop Juergen Gross
@ 2021-05-14 17:05 ` Julien Grall
2021-05-17 6:10 ` Juergen Gross
0 siblings, 1 reply; 8+ messages in thread
From: Julien Grall @ 2021-05-14 17:05 UTC (permalink / raw)
To: Juergen Gross, xen-devel; +Cc: Ian Jackson, Wei Liu
Hi Juergen,
On 14/05/2021 12:56, Juergen Gross wrote:
> The main loop of xenstored is rather complicated due to different
> handling of socket and ring-page interfaces. Unify that handling by
> introducing interface type specific functions can_read() and
> can_write().
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> V2:
> - split off function vector introduction (Julien Grall)
> ---
> tools/xenstore/xenstored_core.c | 77 +++++++++++++++----------------
> tools/xenstore/xenstored_core.h | 2 +
> tools/xenstore/xenstored_domain.c | 2 +
> 3 files changed, 41 insertions(+), 40 deletions(-)
>
> diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
> index 856f518075..883a1a582a 100644
> --- a/tools/xenstore/xenstored_core.c
> +++ b/tools/xenstore/xenstored_core.c
> @@ -1659,9 +1659,34 @@ static int readfd(struct connection *conn, void *data, unsigned int len)
> return rc;
> }
>
> +static bool socket_can_process(struct connection *conn, int mask)
> +{
> + if (conn->pollfd_idx == -1)
> + return false;
> +
> + if (fds[conn->pollfd_idx].revents & ~(POLLIN | POLLOUT)) {
> + talloc_free(conn);
> + return false;
> + }
> +
> + return (fds[conn->pollfd_idx].revents & mask) && !conn->is_ignored;
> +}
> +
> +static bool socket_can_write(struct connection *conn)
> +{
> + return socket_can_process(conn, POLLOUT);
> +}
> +
> +static bool socket_can_read(struct connection *conn)
> +{
> + return socket_can_process(conn, POLLIN);
> +}
> +
> const struct interface_funcs socket_funcs = {
> .write = writefd,
> .read = readfd,
> + .can_write = socket_can_write,
> + .can_read = socket_can_read,
> };
>
> static void accept_connection(int sock)
> @@ -2296,47 +2321,19 @@ int main(int argc, char *argv[])
> if (&next->list != &connections)
> talloc_increase_ref_count(next);
>
> - if (conn->domain) {
> - if (domain_can_read(conn))
> - handle_input(conn);
> - if (talloc_free(conn) == 0)
> - continue;
> -
> - talloc_increase_ref_count(conn);
> - if (domain_can_write(conn) &&
> - !list_empty(&conn->out_list))
AFAICT, the check "!list_empty(&conn->out_list)" can be safely removed
because write_messages() will check if the list is empty (list_top()
returns NULL in this case). Is that correct?
Cheers,
--
Julien Grall
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct
2021-05-14 16:33 ` Julien Grall
@ 2021-05-17 6:07 ` Juergen Gross
0 siblings, 0 replies; 8+ messages in thread
From: Juergen Gross @ 2021-05-17 6:07 UTC (permalink / raw)
To: Julien Grall, xen-devel; +Cc: Ian Jackson, Wei Liu
[-- Attachment #1.1.1: Type: text/plain, Size: 1039 bytes --]
On 14.05.21 18:33, Julien Grall wrote:
> Hi Juergen,
>
> On 14/05/2021 12:56, Juergen Gross wrote:
>> -struct connection *new_connection(connwritefn_t *write, connreadfn_t
>> *read);
>> +struct connection *new_connection(const struct interface_funcs *funcs);
>> struct connection *get_connection_by_id(unsigned int conn_id);
>> void check_store(void);
>> void corrupt(struct connection *conn, const char *fmt, ...);
>> @@ -254,10 +256,7 @@ void finish_daemonize(void);
>> /* Open a pipe for signal handling */
>> void init_pipe(int reopen_log_pipe[2]);
>> -int writefd(struct connection *conn, const void *data, unsigned int
>> len);
>> -int readfd(struct connection *conn, void *data, unsigned int len);
>> -
>> -extern struct interface_funcs socket_funcs;
>> +extern const struct interface_funcs socket_funcs;
> Shouldn't this be protected with #ifdef NO_SOCKETS?
Yes, I can add it.
>
> The rest looks good to me:
>
> Reviewed-by: Julien Grall <jgrall@amazon.com>
Thanks,
Juergen
[-- Attachment #1.1.2: OpenPGP_0xB0DE9DD628BF132F.asc --]
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[-- Attachment #2: OpenPGP digital signature --]
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop
2021-05-14 17:05 ` Julien Grall
@ 2021-05-17 6:10 ` Juergen Gross
2021-05-17 17:54 ` Julien Grall
0 siblings, 1 reply; 8+ messages in thread
From: Juergen Gross @ 2021-05-17 6:10 UTC (permalink / raw)
To: Julien Grall, xen-devel; +Cc: Ian Jackson, Wei Liu
[-- Attachment #1.1.1: Type: text/plain, Size: 2926 bytes --]
On 14.05.21 19:05, Julien Grall wrote:
> Hi Juergen,
>
> On 14/05/2021 12:56, Juergen Gross wrote:
>> The main loop of xenstored is rather complicated due to different
>> handling of socket and ring-page interfaces. Unify that handling by
>> introducing interface type specific functions can_read() and
>> can_write().
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>> V2:
>> - split off function vector introduction (Julien Grall)
>> ---
>> tools/xenstore/xenstored_core.c | 77 +++++++++++++++----------------
>> tools/xenstore/xenstored_core.h | 2 +
>> tools/xenstore/xenstored_domain.c | 2 +
>> 3 files changed, 41 insertions(+), 40 deletions(-)
>>
>> diff --git a/tools/xenstore/xenstored_core.c
>> b/tools/xenstore/xenstored_core.c
>> index 856f518075..883a1a582a 100644
>> --- a/tools/xenstore/xenstored_core.c
>> +++ b/tools/xenstore/xenstored_core.c
>> @@ -1659,9 +1659,34 @@ static int readfd(struct connection *conn, void
>> *data, unsigned int len)
>> return rc;
>> }
>> +static bool socket_can_process(struct connection *conn, int mask)
>> +{
>> + if (conn->pollfd_idx == -1)
>> + return false;
>> +
>> + if (fds[conn->pollfd_idx].revents & ~(POLLIN | POLLOUT)) {
>> + talloc_free(conn);
>> + return false;
>> + }
>> +
>> + return (fds[conn->pollfd_idx].revents & mask) && !conn->is_ignored;
>> +}
>> +
>> +static bool socket_can_write(struct connection *conn)
>> +{
>> + return socket_can_process(conn, POLLOUT);
>> +}
>> +
>> +static bool socket_can_read(struct connection *conn)
>> +{
>> + return socket_can_process(conn, POLLIN);
>> +}
>> +
>> const struct interface_funcs socket_funcs = {
>> .write = writefd,
>> .read = readfd,
>> + .can_write = socket_can_write,
>> + .can_read = socket_can_read,
>> };
>> static void accept_connection(int sock)
>> @@ -2296,47 +2321,19 @@ int main(int argc, char *argv[])
>> if (&next->list != &connections)
>> talloc_increase_ref_count(next);
>> - if (conn->domain) {
>> - if (domain_can_read(conn))
>> - handle_input(conn);
>> - if (talloc_free(conn) == 0)
>> - continue;
>> -
>> - talloc_increase_ref_count(conn);
>> - if (domain_can_write(conn) &&
>> - !list_empty(&conn->out_list))
>
> AFAICT, the check "!list_empty(&conn->out_list)" can be safely removed
> because write_messages() will check if the list is empty (list_top()
> returns NULL in this case). Is that correct?
Yes.
Juergen
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop
2021-05-17 6:10 ` Juergen Gross
@ 2021-05-17 17:54 ` Julien Grall
0 siblings, 0 replies; 8+ messages in thread
From: Julien Grall @ 2021-05-17 17:54 UTC (permalink / raw)
To: Juergen Gross, xen-devel; +Cc: Ian Jackson, Wei Liu
Hi Juergen,
On 17/05/2021 07:10, Juergen Gross wrote:
> On 14.05.21 19:05, Julien Grall wrote:
>> Hi Juergen,
>>
>> On 14/05/2021 12:56, Juergen Gross wrote:
>>> The main loop of xenstored is rather complicated due to different
>>> handling of socket and ring-page interfaces. Unify that handling by
>>> introducing interface type specific functions can_read() and
>>> can_write().
>>>
>>> Signed-off-by: Juergen Gross <jgross@suse.com>
>>> ---
>>> V2:
>>> - split off function vector introduction (Julien Grall)
>>> ---
>>> tools/xenstore/xenstored_core.c | 77 +++++++++++++++----------------
>>> tools/xenstore/xenstored_core.h | 2 +
>>> tools/xenstore/xenstored_domain.c | 2 +
>>> 3 files changed, 41 insertions(+), 40 deletions(-)
>>>
>>> diff --git a/tools/xenstore/xenstored_core.c
>>> b/tools/xenstore/xenstored_core.c
>>> index 856f518075..883a1a582a 100644
>>> --- a/tools/xenstore/xenstored_core.c
>>> +++ b/tools/xenstore/xenstored_core.c
>>> @@ -1659,9 +1659,34 @@ static int readfd(struct connection *conn,
>>> void *data, unsigned int len)
>>> return rc;
>>> }
>>> +static bool socket_can_process(struct connection *conn, int mask)
>>> +{
>>> + if (conn->pollfd_idx == -1)
>>> + return false;
>>> +
>>> + if (fds[conn->pollfd_idx].revents & ~(POLLIN | POLLOUT)) {
>>> + talloc_free(conn);
>>> + return false;
>>> + }
>>> +
>>> + return (fds[conn->pollfd_idx].revents & mask) && !conn->is_ignored;
>>> +}
>>> +
>>> +static bool socket_can_write(struct connection *conn)
>>> +{
>>> + return socket_can_process(conn, POLLOUT);
>>> +}
>>> +
>>> +static bool socket_can_read(struct connection *conn)
>>> +{
>>> + return socket_can_process(conn, POLLIN);
>>> +}
>>> +
>>> const struct interface_funcs socket_funcs = {
>>> .write = writefd,
>>> .read = readfd,
>>> + .can_write = socket_can_write,
>>> + .can_read = socket_can_read,
>>> };
>>> static void accept_connection(int sock)
>>> @@ -2296,47 +2321,19 @@ int main(int argc, char *argv[])
>>> if (&next->list != &connections)
>>> talloc_increase_ref_count(next);
>>> - if (conn->domain) {
>>> - if (domain_can_read(conn))
>>> - handle_input(conn);
>>> - if (talloc_free(conn) == 0)
>>> - continue;
>>> -
>>> - talloc_increase_ref_count(conn);
>>> - if (domain_can_write(conn) &&
>>> - !list_empty(&conn->out_list))
>>
>> AFAICT, the check "!list_empty(&conn->out_list)" can be safely removed
>> because write_messages() will check if the list is empty (list_top()
>> returns NULL in this case). Is that correct?
>
> Yes.
Thanks, how about adding in the commit message:
"Take the opportunity to remove the empty list check before calling
write_messages() because the function is already able to cope with an
empty list."
I can update the commit message while committing it.
Cheers,
--
Julien Grall
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-05-17 17:54 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-14 11:56 [PATCH v2 0/2] tools/xenstore: simplify xenstored main loop Juergen Gross
2021-05-14 11:56 ` [PATCH v2 1/2] tools/xenstore: move per connection read and write func hooks into a struct Juergen Gross
2021-05-14 16:33 ` Julien Grall
2021-05-17 6:07 ` Juergen Gross
2021-05-14 11:56 ` [PATCH v2 2/2] tools/xenstore: simplify xenstored main loop Juergen Gross
2021-05-14 17:05 ` Julien Grall
2021-05-17 6:10 ` Juergen Gross
2021-05-17 17:54 ` Julien Grall
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