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From: Luca Fancellu <luca.fancellu@arm.com>
To: Julien Grall <julien@xen.org>
Cc: xen-devel@lists.xenproject.org, raphning@amazon.co.uk,
	doebel@amazon.de, Julien Grall <jgrall@amazon.com>,
	Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
	Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH 06/10] tools/xenstored: Introduce a wrapper for conn->funcs->can_{read, write}
Date: Mon, 21 Jun 2021 10:10:58 +0100	[thread overview]
Message-ID: <73401908-D406-4ED8-93FA-C0A0911651BF@arm.com> (raw)
In-Reply-To: <20210616144324.31652-7-julien@xen.org>



> 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
> 
> 



  reply	other threads:[~2021-06-21  9:12 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16 14:43 [PATCH 00/10] tools/xenstored: Bug fixes + Improve Live-Update Julien Grall
2021-06-16 14:43 ` [PATCH 01/10] MAINTAINERS: Add myself as reviewers for tools/xenstore Julien Grall
2021-06-16 15:15   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 02/10] tools/xenstored: Introduce lu_get_connection() and use it Julien Grall
2021-06-21  8:21   ` Luca Fancellu
2021-06-24  7:21   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 03/10] tools/xenstore: Don't assume conn->in points to the LU request Julien Grall
2021-06-21  8:55   ` Luca Fancellu
2021-06-24  8:06     ` Julien Grall
2021-06-24  7:32   ` Juergen Gross
2021-06-24  7:34     ` Juergen Gross
2021-06-24  7:56       ` Luca Fancellu
2021-06-24  8:05         ` Juergen Gross
2021-06-16 14:43 ` [PATCH 04/10] tools/xenstored: Limit the number of requests a connection can delay Julien Grall
2021-06-21  9:02   ` Luca Fancellu
2021-06-24  7:35   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 05/10] tools/xenstored: xenstored_core.h should include fcntl.h Julien Grall
2021-06-21  9:03   ` Luca Fancellu
2021-06-24  7:36   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 06/10] tools/xenstored: Introduce a wrapper for conn->funcs->can_{read, write} Julien Grall
2021-06-21  9:10   ` Luca Fancellu [this message]
2021-06-24  7:39   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 07/10] tools/xenstored: delay_request: don't assume conn->in == in Julien Grall
2021-06-21  9:12   ` Luca Fancellu
2021-06-24  7:44   ` Juergen Gross
2021-06-24  7:58     ` Julien Grall
2021-06-16 14:43 ` [PATCH 08/10] tools/xenstored: Extend restore code to handle multiple input buffer Julien Grall
2021-06-21  9:21   ` Luca Fancellu
2021-06-24  8:30   ` Juergen Gross
2021-06-24  8:42     ` Julien Grall
2021-06-24  9:20       ` Juergen Gross
2021-06-16 14:43 ` [PATCH 09/10] tools/xenstored: Dump delayed requests Julien Grall
2021-06-21  9:27   ` Luca Fancellu
2021-06-24  8:41   ` Juergen Gross
2021-06-24 10:28     ` Julien Grall
2021-06-24 10:45       ` Juergen Gross
2021-06-24 10:46         ` Julien Grall
2021-06-24 11:02           ` Juergen Gross
2021-06-24 11:17             ` Julien Grall
2021-06-16 14:43 ` [PATCH 10/10] tools/xenstored: Delay new transaction while Live-Update is pending Julien Grall
2021-06-21  9:30   ` Luca Fancellu
2021-06-24  9:23   ` Juergen Gross
2021-06-24 10:43 ` [PATCH 00/10] tools/xenstored: Bug fixes + Improve Live-Update Julien Grall

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