diff mbox series

[06/10] tools/xenstored: Introduce a wrapper for conn->funcs->can_{read, write}

Message ID 20210616144324.31652-7-julien@xen.org (mailing list archive)
State New, archived
Headers show
Series tools/xenstored: Bug fixes + Improve Live-Update | expand

Commit Message

Julien Grall June 16, 2021, 2:43 p.m. UTC 
From: Julien Grall <jgrall@amazon.com>

Currently, the callbacks can_read and can_write are called directly. This
doesn't allow us to add generic check and therefore requires duplication.

At the moment, one check that could benefit to be common is whether the
connection should ignored. The position is slightly different between
domain and socket because for the latter we want to check the state of
the file descriptor first.

In follow-up patches, there will be more potential generic checks.

This patch provides wrappers to read/write a connection and move
the check ->is_ignored after the callback for everyone.

This also requires to replace the direct call to domain_can_read()
and domain_can_write() with the new wrapper. At the same time,
both functions can now be static. Note that the implementations need
to be moved earlier in the file xenstored_domain.c to avoid
declaring the prototype.

Signed-off-by: Julien Grall <jgrall@amazon.com>
---
 tools/xenstore/xenstored_core.c   | 18 ++++++++++----
 tools/xenstore/xenstored_domain.c | 40 +++++++++++++------------------
 tools/xenstore/xenstored_domain.h |  4 ----
 3 files changed, 31 insertions(+), 31 deletions(-)

Comments

Luca Fancellu June 21, 2021, 9:10 a.m. UTC | #1 
> On 16 Jun 2021, at 15:43, Julien Grall <julien@xen.org> wrote:
> 
> From: Julien Grall <jgrall@amazon.com>
> 
> Currently, the callbacks can_read and can_write are called directly. This
> doesn't allow us to add generic check and therefore requires duplication.
> 
> At the moment, one check that could benefit to be common is whether the
> connection should ignored. The position is slightly different between
> domain and socket because for the latter we want to check the state of
> the file descriptor first.
> 
> In follow-up patches, there will be more potential generic checks.
> 
> This patch provides wrappers to read/write a connection and move
> the check ->is_ignored after the callback for everyone.
> 
> This also requires to replace the direct call to domain_can_read()
> and domain_can_write() with the new wrapper. At the same time,
> both functions can now be static. Note that the implementations need
> to be moved earlier in the file xenstored_domain.c to avoid
> declaring the prototype.
> 
> Signed-off-by: Julien Grall <jgrall@amazon.com>

Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>

> ---
> tools/xenstore/xenstored_core.c   | 18 ++++++++++----
> tools/xenstore/xenstored_domain.c | 40 +++++++++++++------------------
> tools/xenstore/xenstored_domain.h |  4 ----
> 3 files changed, 31 insertions(+), 31 deletions(-)
> 
> diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
> index 51d210828922..2e5760fe4599 100644
> --- a/tools/xenstore/xenstored_core.c
> +++ b/tools/xenstore/xenstored_core.c
> @@ -334,6 +334,16 @@ static int destroy_conn(void *_conn)
> 	return 0;
> }
> 
> +static bool conn_can_read(struct connection *conn)
> +{
> +	return conn->funcs->can_read(conn) && !conn->is_ignored;
> +}
> +
> +static bool conn_can_write(struct connection *conn)
> +{
> +	return conn->funcs->can_write(conn) && !conn->is_ignored;
> +}
> +
> /* This function returns index inside the array if succeed, -1 if fail */
> static int set_fd(int fd, short events)
> {
> @@ -396,8 +406,8 @@ static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout)
> 	list_for_each_entry(conn, &connections, list) {
> 		if (conn->domain) {
> 			wrl_check_timeout(conn->domain, now, ptimeout);
> -			if (domain_can_read(conn) ||
> -			    (domain_can_write(conn) &&
> +			if (conn_can_read(conn) ||
> +			    (conn_can_write(conn) &&
> 			     !list_empty(&conn->out_list)))
> 				*ptimeout = 0;
> 		} else {
> @@ -2325,14 +2335,14 @@ int main(int argc, char *argv[])
> 			if (&next->list != &connections)
> 				talloc_increase_ref_count(next);
> 
> -			if (conn->funcs->can_read(conn))
> +			if (conn_can_read(conn))
> 				handle_input(conn);
> 			if (talloc_free(conn) == 0)
> 				continue;
> 
> 			talloc_increase_ref_count(conn);
> 
> -			if (conn->funcs->can_write(conn))
> +			if (conn_can_write(conn))
> 				handle_output(conn);
> 			if (talloc_free(conn) == 0)
> 				continue;
> diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
> index 6d8d29cbe41c..47e9107c144e 100644
> --- a/tools/xenstore/xenstored_domain.c
> +++ b/tools/xenstore/xenstored_domain.c
> @@ -172,6 +172,23 @@ static int readchn(struct connection *conn, void *data, unsigned int len)
> 	return len;
> }
> 
> +static bool domain_can_write(struct connection *conn)
> +{
> +	struct xenstore_domain_interface *intf = conn->domain->interface;
> +
> +	return ((intf->rsp_prod - intf->rsp_cons) != XENSTORE_RING_SIZE);
> +}
> +
> +static bool domain_can_read(struct connection *conn)
> +{
> +	struct xenstore_domain_interface *intf = conn->domain->interface;
> +
> +	if (domain_is_unprivileged(conn) && conn->domain->wrl_credit < 0)
> +		return false;
> +
> +	return (intf->req_cons != intf->req_prod);
> +}
> +
> static const struct interface_funcs domain_funcs = {
> 	.write = writechn,
> 	.read = readchn,
> @@ -290,19 +307,6 @@ void handle_event(void)
> 		barf_perror("Failed to write to event fd");
> }
> 
> -bool domain_can_read(struct connection *conn)
> -{
> -	struct xenstore_domain_interface *intf = conn->domain->interface;
> -
> -	if (domain_is_unprivileged(conn) && conn->domain->wrl_credit < 0)
> -		return false;
> -
> -	if (conn->is_ignored)
> -		return false;
> -
> -	return (intf->req_cons != intf->req_prod);
> -}
> -
> static bool domid_is_unprivileged(unsigned int domid)
> {
> 	return domid != 0 && domid != priv_domid;
> @@ -314,16 +318,6 @@ bool domain_is_unprivileged(struct connection *conn)
> 	       domid_is_unprivileged(conn->domain->domid);
> }
> 
> -bool domain_can_write(struct connection *conn)
> -{
> -	struct xenstore_domain_interface *intf = conn->domain->interface;
> -
> -	if (conn->is_ignored)
> -		return false;
> -
> -	return ((intf->rsp_prod - intf->rsp_cons) != XENSTORE_RING_SIZE);
> -}
> -
> static char *talloc_domain_path(void *context, unsigned int domid)
> {
> 	return talloc_asprintf(context, "/local/domain/%u", domid);
> diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
> index 62ee471ea6aa..1e929b8f8c6f 100644
> --- a/tools/xenstore/xenstored_domain.h
> +++ b/tools/xenstore/xenstored_domain.h
> @@ -51,10 +51,6 @@ void domain_deinit(void);
> /* Returns the implicit path of a connection (only domains have this) */
> const char *get_implicit_path(const struct connection *conn);
> 
> -/* Can connection attached to domain read/write. */
> -bool domain_can_read(struct connection *conn);
> -bool domain_can_write(struct connection *conn);
> -
> bool domain_is_unprivileged(struct connection *conn);
> 
> /* Remove node permissions for no longer existing domains. */
> -- 
> 2.17.1
> 
>
Jürgen Groß June 24, 2021, 7:39 a.m. UTC | #2 
On 16.06.21 16:43, Julien Grall wrote:
> From: Julien Grall <jgrall@amazon.com>
> 
> Currently, the callbacks can_read and can_write are called directly. This
> doesn't allow us to add generic check and therefore requires duplication.
> 
> At the moment, one check that could benefit to be common is whether the
> connection should ignored. The position is slightly different between
> domain and socket because for the latter we want to check the state of
> the file descriptor first.
> 
> In follow-up patches, there will be more potential generic checks.
> 
> This patch provides wrappers to read/write a connection and move
> the check ->is_ignored after the callback for everyone.
> 
> This also requires to replace the direct call to domain_can_read()
> and domain_can_write() with the new wrapper. At the same time,
> both functions can now be static. Note that the implementations need
> to be moved earlier in the file xenstored_domain.c to avoid
> declaring the prototype.
> 
> Signed-off-by: Julien Grall <jgrall@amazon.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen
diff mbox series

Patch

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 51d210828922..2e5760fe4599 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -334,6 +334,16 @@  static int destroy_conn(void *_conn)
 	return 0;
 }
 
+static bool conn_can_read(struct connection *conn)
+{
+	return conn->funcs->can_read(conn) && !conn->is_ignored;
+}
+
+static bool conn_can_write(struct connection *conn)
+{
+	return conn->funcs->can_write(conn) && !conn->is_ignored;
+}
+
 /* This function returns index inside the array if succeed, -1 if fail */
 static int set_fd(int fd, short events)
 {
@@ -396,8 +406,8 @@  static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout)
 	list_for_each_entry(conn, &connections, list) {
 		if (conn->domain) {
 			wrl_check_timeout(conn->domain, now, ptimeout);
-			if (domain_can_read(conn) ||
-			    (domain_can_write(conn) &&
+			if (conn_can_read(conn) ||
+			    (conn_can_write(conn) &&
 			     !list_empty(&conn->out_list)))
 				*ptimeout = 0;
 		} else {
@@ -2325,14 +2335,14 @@  int main(int argc, char *argv[])
 			if (&next->list != &connections)
 				talloc_increase_ref_count(next);
 
-			if (conn->funcs->can_read(conn))
+			if (conn_can_read(conn))
 				handle_input(conn);
 			if (talloc_free(conn) == 0)
 				continue;
 
 			talloc_increase_ref_count(conn);
 
-			if (conn->funcs->can_write(conn))
+			if (conn_can_write(conn))
 				handle_output(conn);
 			if (talloc_free(conn) == 0)
 				continue;
diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index 6d8d29cbe41c..47e9107c144e 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -172,6 +172,23 @@  static int readchn(struct connection *conn, void *data, unsigned int len)
 	return len;
 }
 
+static bool domain_can_write(struct connection *conn)
+{
+	struct xenstore_domain_interface *intf = conn->domain->interface;
+
+	return ((intf->rsp_prod - intf->rsp_cons) != XENSTORE_RING_SIZE);
+}
+
+static bool domain_can_read(struct connection *conn)
+{
+	struct xenstore_domain_interface *intf = conn->domain->interface;
+
+	if (domain_is_unprivileged(conn) && conn->domain->wrl_credit < 0)
+		return false;
+
+	return (intf->req_cons != intf->req_prod);
+}
+
 static const struct interface_funcs domain_funcs = {
 	.write = writechn,
 	.read = readchn,
@@ -290,19 +307,6 @@  void handle_event(void)
 		barf_perror("Failed to write to event fd");
 }
 
-bool domain_can_read(struct connection *conn)
-{
-	struct xenstore_domain_interface *intf = conn->domain->interface;
-
-	if (domain_is_unprivileged(conn) && conn->domain->wrl_credit < 0)
-		return false;
-
-	if (conn->is_ignored)
-		return false;
-
-	return (intf->req_cons != intf->req_prod);
-}
-
 static bool domid_is_unprivileged(unsigned int domid)
 {
 	return domid != 0 && domid != priv_domid;
@@ -314,16 +318,6 @@  bool domain_is_unprivileged(struct connection *conn)
 	       domid_is_unprivileged(conn->domain->domid);
 }
 
-bool domain_can_write(struct connection *conn)
-{
-	struct xenstore_domain_interface *intf = conn->domain->interface;
-
-	if (conn->is_ignored)
-		return false;
-
-	return ((intf->rsp_prod - intf->rsp_cons) != XENSTORE_RING_SIZE);
-}
-
 static char *talloc_domain_path(void *context, unsigned int domid)
 {
 	return talloc_asprintf(context, "/local/domain/%u", domid);
diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
index 62ee471ea6aa..1e929b8f8c6f 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -51,10 +51,6 @@  void domain_deinit(void);
 /* Returns the implicit path of a connection (only domains have this) */
 const char *get_implicit_path(const struct connection *conn);
 
-/* Can connection attached to domain read/write. */
-bool domain_can_read(struct connection *conn);
-bool domain_can_write(struct connection *conn);
-
 bool domain_is_unprivileged(struct connection *conn);
 
 /* Remove node permissions for no longer existing domains. */