git: a133f64239cd - main - hwpmc: split out PMC_OP_PMCATTACH/PMC_OP_PMCDETACH

The branch main has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=a133f64239cdbefa374cf6df134f3581f9b9f147

commit a133f64239cdbefa374cf6df134f3581f9b9f147
Author:     Mitchell Horne <mhorne@FreeBSD.org>
AuthorDate: 2023-06-14 16:32:11 +0000
Commit:     Mitchell Horne <mhorne@FreeBSD.org>
CommitDate: 2023-06-14 16:34:21 +0000

    hwpmc: split out PMC_OP_PMCATTACH/PMC_OP_PMCDETACH
    
    Begin splitting out the large chunks of functional logic from the
    syscall handler into separate helper functions. This keeps it separate
    from the syscall control-flow logic, resulting in better readability
    overall. It also wins back a level of indentation.
    
    For this and the similar changes to follow, try to keep copyin() and
    copyout() calls outside of the helper functions. The changes are
    intended to have no functional impact, but do address style issues.
    
    Reviewed by:    jkoshy
    MFC after:      2 weeks
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D40291
---
 sys/dev/hwpmc/hwpmc_mod.c | 190 +++++++++++++++++++++++++---------------------
 1 file changed, 103 insertions(+), 87 deletions(-)

diff --git a/sys/dev/hwpmc/hwpmc_mod.c b/sys/dev/hwpmc/hwpmc_mod.c
index 987184b7fae8..24cd3ba0fc0f 100644
--- a/sys/dev/hwpmc/hwpmc_mod.c
+++ b/sys/dev/hwpmc/hwpmc_mod.c
@@ -3282,6 +3282,103 @@ static const char *pmc_op_to_name[] = {
 	is_sx_downgraded = true;		\
 } while (0)
 
+/*
+ * Main body of PMC_OP_PMCATTACH.
+ */
+static int
+pmc_do_op_pmcattach(struct thread *td, struct pmc_op_pmcattach a)
+{
+	struct pmc *pm;
+	struct proc *p;
+	int error;
+
+	sx_assert(&pmc_sx, SX_XLOCKED);
+
+	if (a.pm_pid < 0) {
+		return (EINVAL);
+	} else if (a.pm_pid == 0) {
+		a.pm_pid = td->td_proc->p_pid;
+	}
+
+	error = pmc_find_pmc(a.pm_pmc, &pm);
+	if (error != 0)
+		return (error);
+
+	if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm)))
+		return (EINVAL);
+
+	/* PMCs may be (re)attached only when allocated or stopped */
+	if (pm->pm_state == PMC_STATE_RUNNING) {
+		return (EBUSY);
+	} else if (pm->pm_state != PMC_STATE_ALLOCATED &&
+	    pm->pm_state != PMC_STATE_STOPPED) {
+		return (EINVAL);
+	}
+
+	/* lookup pid */
+	if ((p = pfind(a.pm_pid)) == NULL)
+		return (ESRCH);
+
+	/*
+	 * Ignore processes that are working on exiting.
+	 */
+	if ((p->p_flag & P_WEXIT) != 0) {
+		PROC_UNLOCK(p);	/* pfind() returns a locked process */
+		return (ESRCH);
+	}
+
+	/*
+	 * We are allowed to attach a PMC to a process if we can debug it.
+	 */
+	error = p_candebug(curthread, p);
+
+	PROC_UNLOCK(p);
+
+	if (error == 0)
+		error = pmc_attach_process(p, pm);
+
+	return (error);
+}
+
+/*
+ * Main body of PMC_OP_PMCDETACH.
+ */
+static int
+pmc_do_op_pmcdetach(struct thread *td, struct pmc_op_pmcattach a)
+{
+	struct pmc *pm;
+	struct proc *p;
+	int error;
+
+	if (a.pm_pid < 0) {
+		return (EINVAL);
+	} else if (a.pm_pid == 0)
+		a.pm_pid = td->td_proc->p_pid;
+
+	error = pmc_find_pmc(a.pm_pmc, &pm);
+	if (error != 0)
+		return (error);
+
+	if ((p = pfind(a.pm_pid)) == NULL)
+		return (ESRCH);
+
+	/*
+	 * Treat processes that are in the process of exiting as if they were
+	 * not present.
+	 */
+	if ((p->p_flag & P_WEXIT) != 0) {
+		PROC_UNLOCK(p);
+		return (ESRCH);
+	}
+
+	PROC_UNLOCK(p);	/* pfind() returns a locked process */
+
+	if (error == 0)
+		error = pmc_detach_process(p, pm);
+
+	return (error);
+}
+
 static int
 pmc_syscall_handler(struct thread *td, void *syscall_args)
 {
@@ -4004,114 +4101,33 @@ pmc_syscall_handler(struct thread *td, void *syscall_args)
 	}
 	break;
 
-
 	/*
 	 * Attach a PMC to a process.
 	 */
-
 	case PMC_OP_PMCATTACH:
 	{
-		struct pmc *pm;
-		struct proc *p;
 		struct pmc_op_pmcattach a;
 
-		sx_assert(&pmc_sx, SX_XLOCKED);
-
-		if ((error = copyin(arg, &a, sizeof(a))) != 0)
-			break;
-
-		if (a.pm_pid < 0) {
-			error = EINVAL;
-			break;
-		} else if (a.pm_pid == 0)
-			a.pm_pid = td->td_proc->p_pid;
-
-		if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
-			break;
-
-		if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm))) {
-			error = EINVAL;
-			break;
-		}
-
-		/* PMCs may be (re)attached only when allocated or stopped */
-		if (pm->pm_state == PMC_STATE_RUNNING) {
-			error = EBUSY;
-			break;
-		} else if (pm->pm_state != PMC_STATE_ALLOCATED &&
-		    pm->pm_state != PMC_STATE_STOPPED) {
-			error = EINVAL;
-			break;
-		}
-
-		/* lookup pid */
-		if ((p = pfind(a.pm_pid)) == NULL) {
-			error = ESRCH;
-			break;
-		}
-
-		/*
-		 * Ignore processes that are working on exiting.
-		 */
-		if (p->p_flag & P_WEXIT) {
-			error = ESRCH;
-			PROC_UNLOCK(p);	/* pfind() returns a locked process */
+		error = copyin(arg, &a, sizeof(a));
+		if (error != 0)
 			break;
-		}
 
-		/*
-		 * we are allowed to attach a PMC to a process if
-		 * we can debug it.
-		 */
-		error = p_candebug(curthread, p);
-
-		PROC_UNLOCK(p);
-
-		if (error == 0)
-			error = pmc_attach_process(p, pm);
+		error = pmc_do_op_pmcattach(td, a);
 	}
 	break;
 
-
 	/*
 	 * Detach an attached PMC from a process.
 	 */
-
 	case PMC_OP_PMCDETACH:
 	{
-		struct pmc *pm;
-		struct proc *p;
 		struct pmc_op_pmcattach a;
 
-		if ((error = copyin(arg, &a, sizeof(a))) != 0)
-			break;
-
-		if (a.pm_pid < 0) {
-			error = EINVAL;
-			break;
-		} else if (a.pm_pid == 0)
-			a.pm_pid = td->td_proc->p_pid;
-
-		if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
-			break;
-
-		if ((p = pfind(a.pm_pid)) == NULL) {
-			error = ESRCH;
+		error = copyin(arg, &a, sizeof(a));
+		if (error != 0)
 			break;
-		}
 
-		/*
-		 * Treat processes that are in the process of exiting
-		 * as if they were not present.
-		 */
-
-		if (p->p_flag & P_WEXIT)
-			error = ESRCH;
-
-		PROC_UNLOCK(p);	/* pfind() returns a locked process */
-
-		if (error == 0)
-			error = pmc_detach_process(p, pm);
+		error = pmc_do_op_pmcdetach(td, a);
 	}
 	break;