Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:57431 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750883AbcEDN2A (ORCPT ); Wed, 4 May 2016 09:28:00 -0400 Subject: Re: [PATCH 2/2] gssd: move read of upcall into main thread To: Olga Kornievskaia References: <1462286792-8889-1-git-send-email-kolga@netapp.com> <1462286792-8889-2-git-send-email-kolga@netapp.com> Cc: linux-nfs@vger.kernel.org From: Steve Dickson Message-ID: <50edf6a8-4d4c-07d5-af0a-363ac66dbfa5@RedHat.com> Date: Wed, 4 May 2016 09:27:58 -0400 MIME-Version: 1.0 In-Reply-To: <1462286792-8889-2-git-send-email-kolga@netapp.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-nfs-owner@vger.kernel.org List-ID: One very small nit... On 05/03/2016 10:46 AM, Olga Kornievskaia wrote: > This patch moves reading of the upcall information from the child thread > into the main thread. It removes the need to synchronize between the > parent and child thread before processing upcall. Also it creates the thread > in a detached state. > > Signed-off-by: Olga Kornievskaia > --- > utils/gssd/gssd.c | 95 +++++++++++++++++++++++++++++++++++--------------- > utils/gssd/gssd.h | 13 +++++-- > utils/gssd/gssd_proc.c | 73 +++++++++++--------------------------- > 3 files changed, 98 insertions(+), 83 deletions(-) > > diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c > index 9bf7917..95b6715 100644 > --- a/utils/gssd/gssd.c > +++ b/utils/gssd/gssd.c > @@ -363,54 +363,93 @@ gssd_destroy_client(struct clnt_info *clp) > > static void gssd_scan(void); > > -static inline void > -wait_for_child_and_detach(pthread_t th) > +static void > +start_upcall_thread(void (*func)(struct clnt_upcall_info *), void *info) > +{ > + pthread_attr_t attr; > + pthread_t th; > + int ret; > + > + ret = pthread_attr_init(&attr); > + if (ret != 0) { > + printerr(0, "ERROR: failed to init pthread attr: ret %d: %s\n", > + ret, strerror(errno)); > + goto err; > + } > + ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); > + if (ret != 0) { > + printerr(0, "ERROR: failed to create pthread attr: ret %d: " > + "%s\n", ret, strerror(errno)); > + goto err; > + } > + > + ret = pthread_create(&th, &attr, (void *)func, (void *)info); > + if (ret != 0) { > + printerr(0, "ERROR: pthread_create failed: ret %d: %s\n", > + ret, strerror(errno)); > + goto err; > + } > + return; > +err: > + free(info); > +} > + > +static struct clnt_upcall_info *alloc_upcall_info(struct clnt_info *clp) > { > - pthread_mutex_lock(&pmutex); > - while (!thread_started) > - pthread_cond_wait(&pcond, &pmutex); > - thread_started = false; > - pthread_mutex_unlock(&pmutex); > - pthread_detach(th); > + struct clnt_upcall_info *info; > + > + info = malloc(sizeof(struct clnt_upcall_info)); > + if (info == NULL) > + return NULL; > + info->clp = clp; > + > + return info; > } > > -/* For each upcall create a thread, detach from the main process so that > - * resources are released back into the system without the need for a join. > - * We need to wait for the child thread to start and consume the event from > - * the file descriptor. > +/* For each upcall read the upcall info into the buffer, then create a > + * thread in a detached state so that resources are released back into > + * the system without the need for a join. > */ > static void > gssd_clnt_gssd_cb(int UNUSED(fd), short UNUSED(which), void *data) > { > struct clnt_info *clp = data; > - pthread_t th; > - int ret; > + struct clnt_upcall_info *info; > > - ret = pthread_create(&th, NULL, (void *)handle_gssd_upcall, > - (void *)clp); > - if (ret != 0) { > - printerr(0, "ERROR: pthread_create failed: ret %d: %s\n", > - ret, strerror(errno)); > + info = alloc_upcall_info(clp); > + if (info == NULL) > + return; > + > + info->lbuflen = read(clp->gssd_fd, info->lbuf, sizeof(info->lbuf)); > + if (info->lbuflen <= 0 || info->lbuf[info->lbuflen-1] != '\n') { > + printerr(0, "WARNING: %s: failed reading request\n", __func__); > + free(info); > return; > } > - wait_for_child_and_detach(th); > + info->lbuf[info->lbuflen-1] = 0; > + > + start_upcall_thread(handle_gssd_upcall, info); Instead of having start_upcall_thread() free the info pointer I think it makes it more readable if gssd_clnt_gssd_cb() does the free... So the routine would allocate the pointer, populate the pointer and free the point all in one routine. I think it would make start_upcall_thread() simpler since it would not need all those goto... steved. > } > > static void > gssd_clnt_krb5_cb(int UNUSED(fd), short UNUSED(which), void *data) > { > struct clnt_info *clp = data; > - pthread_t th; > - int ret; > + struct clnt_upcall_info *info; > > - ret = pthread_create(&th, NULL, (void *)handle_krb5_upcall, > - (void *)clp); > - if (ret != 0) { > - printerr(0, "ERROR: pthread_create failed: ret %d: %s\n", > - ret, strerror(errno)); > + info = alloc_upcall_info(clp); > + if (info == NULL) > + return; > + > + if (read(clp->krb5_fd, &info->uid, > + sizeof(info->uid)) < (ssize_t)sizeof(info->uid)) { > + printerr(0, "WARNING: %s: failed reading uid from krb5 " > + "upcall pipe: %s\n", __func__, strerror(errno)); > + free(info); > return; > } > - wait_for_child_and_detach(th); > + > + start_upcall_thread(handle_krb5_upcall, info); > } > > static struct clnt_info * > diff --git a/utils/gssd/gssd.h b/utils/gssd/gssd.h > index 565bce3..f4f5975 100644 > --- a/utils/gssd/gssd.h > +++ b/utils/gssd/gssd.h > @@ -49,7 +49,7 @@ > #define GSSD_DEFAULT_MACHINE_CRED_SUFFIX "machine" > #define GSSD_DEFAULT_KEYTAB_FILE "/etc/krb5.keytab" > #define GSSD_SERVICE_NAME "nfs" > - > +#define RPC_CHAN_BUF_SIZE 32768 > /* > * The gss mechanisms that we can handle > */ > @@ -85,8 +85,15 @@ struct clnt_info { > struct sockaddr_storage addr; > }; > > -void handle_krb5_upcall(struct clnt_info *clp); > -void handle_gssd_upcall(struct clnt_info *clp); > +struct clnt_upcall_info { > + struct clnt_info *clp; > + char lbuf[RPC_CHAN_BUF_SIZE]; > + int lbuflen; > + uid_t uid; > +}; > + > +void handle_krb5_upcall(struct clnt_upcall_info *clp); > +void handle_gssd_upcall(struct clnt_upcall_info *clp); > > > #endif /* _RPC_GSSD_H_ */ > diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c > index afaaf9e..d74d372 100644 > --- a/utils/gssd/gssd_proc.c > +++ b/utils/gssd/gssd_proc.c > @@ -79,7 +79,6 @@ > #include "nfsrpc.h" > #include "nfslib.h" > #include "gss_names.h" > -#include "misc.h" > > /* Encryption types supported by the kernel rpcsec_gss code */ > int num_krb5_enctypes = 0; > @@ -708,45 +707,22 @@ out_return_error: > goto out; > } > > -/* signal to the parent thread that we have read from the file descriptor. > - * it should allow the parent to proceed to poll on the descriptor for > - * the next upcall from the kernel. > - */ > -static inline void > -signal_parent_event_consumed(void) > -{ > - pthread_mutex_lock(&pmutex); > - thread_started = true; > - pthread_cond_signal(&pcond); > - pthread_mutex_unlock(&pmutex); > -} > - > void > -handle_krb5_upcall(struct clnt_info *clp) > +handle_krb5_upcall(struct clnt_upcall_info *info) > { > - uid_t uid; > - int status; > + struct clnt_info *clp = info->clp; > > - status = read(clp->krb5_fd, &uid, sizeof(uid)) < (ssize_t)sizeof(uid); > - signal_parent_event_consumed(); > + printerr(2, "\n%s: uid %d (%s)\n", __func__, info->uid, clp->relpath); > > - if (status) { > - printerr(0, "WARNING: failed reading uid from krb5 " > - "upcall pipe: %s\n", strerror(errno)); > - return; > - } > - > - printerr(2, "\n%s: uid %d (%s)\n", __func__, uid, clp->relpath); > - > - process_krb5_upcall(clp, uid, clp->krb5_fd, NULL, NULL); > + process_krb5_upcall(clp, info->uid, clp->krb5_fd, NULL, NULL); > + free(info); > } > > void > -handle_gssd_upcall(struct clnt_info *clp) > +handle_gssd_upcall(struct clnt_upcall_info *info) > { > + struct clnt_info *clp = info->clp; > uid_t uid; > - char lbuf[RPC_CHAN_BUF_SIZE]; > - int lbuflen = 0; > char *p; > char *mech = NULL; > char *uidstr = NULL; > @@ -754,19 +730,9 @@ handle_gssd_upcall(struct clnt_info *clp) > char *service = NULL; > char *enctypes = NULL; > > - lbuflen = read(clp->gssd_fd, lbuf, sizeof(lbuf)); > - signal_parent_event_consumed(); > + printerr(2, "\n%s: '%s' (%s)\n", __func__, info->lbuf, clp->relpath); > > - if (lbuflen <= 0 || lbuf[lbuflen-1] != '\n') { > - printerr(0, "WARNING: handle_gssd_upcall: " > - "failed reading request\n"); > - return; > - } > - lbuf[lbuflen-1] = 0; > - > - printerr(2, "\n%s: '%s' (%s)\n", __func__, lbuf, clp->relpath); > - > - for (p = strtok(lbuf, " "); p; p = strtok(NULL, " ")) { > + for (p = strtok(info->lbuf, " "); p; p = strtok(NULL, " ")) { > if (!strncmp(p, "mech=", strlen("mech="))) > mech = p + strlen("mech="); > else if (!strncmp(p, "uid=", strlen("uid="))) > @@ -782,8 +748,8 @@ handle_gssd_upcall(struct clnt_info *clp) > if (!mech || strlen(mech) < 1) { > printerr(0, "WARNING: handle_gssd_upcall: " > "failed to find gss mechanism name " > - "in upcall string '%s'\n", lbuf); > - return; > + "in upcall string '%s'\n", info->lbuf); > + goto out; > } > > if (uidstr) { > @@ -795,21 +761,21 @@ handle_gssd_upcall(struct clnt_info *clp) > if (!uidstr) { > printerr(0, "WARNING: handle_gssd_upcall: " > "failed to find uid " > - "in upcall string '%s'\n", lbuf); > - return; > + "in upcall string '%s'\n", info->lbuf); > + goto out; > } > > if (enctypes && parse_enctypes(enctypes) != 0) { > printerr(0, "WARNING: handle_gssd_upcall: " > "parsing encryption types failed: errno %d\n", errno); > - return; > + goto out; > } > > if (target && strlen(target) < 1) { > printerr(0, "WARNING: handle_gssd_upcall: " > "failed to parse target name " > - "in upcall string '%s'\n", lbuf); > - return; > + "in upcall string '%s'\n", info->lbuf); > + goto out; > } > > /* > @@ -823,8 +789,8 @@ handle_gssd_upcall(struct clnt_info *clp) > if (service && strlen(service) < 1) { > printerr(0, "WARNING: handle_gssd_upcall: " > "failed to parse service type " > - "in upcall string '%s'\n", lbuf); > - return; > + "in upcall string '%s'\n", info->lbuf); > + goto out; > } > > if (strcmp(mech, "krb5") == 0 && clp->servername) > @@ -835,5 +801,8 @@ handle_gssd_upcall(struct clnt_info *clp) > "received unknown gss mech '%s'\n", mech); > do_error_downcall(clp->gssd_fd, uid, -EACCES); > } > +out: > + free(info); > + return; > } > >